TestFlight crash
AIAbOarIhXtETbisVWXN7mgComment
Crash after launch
Crash log
Incident Identifier: 30868BE5-DE55-4FAB-A0C7-434DF14D4F55
Distributor ID: com.apple.TestFlight
Hardware Model: iPad17,4
Process: HydraHeadiPad [1419]
Path: /private/var/containers/Bundle/Application/74DFDB54-DBE3-484F-AD22-3B39156E83F8/HydraHeadiPad.app/HydraHeadiPad
Identifier: com.experiencenet.hydraheadipad
Version: 0.2.60 (83)
AppStoreTools: 17F41
AppVariant: 1:iPad17,4-A:26
Beta: YES
Code Type: ARM-64 (Native)
Role: Foreground
Parent Process: launchd [1]
Coalition: com.experiencenet.hydraheadipad [991]
Date/Time: 2026-05-19 17:54:53.2934 +0200
Launch Time: 2026-05-19 17:54:50.0952 +0200
OS Version: iPhone OS 26.3 (23D127)
Release Type: User
Baseband Version: 2.03.08
Report Version: 104
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Reason: -[%s %s]: unrecognized selector sent to instance 0x11af43700
Termination Reason: SIGNAL 6 Abort trap: 6
Terminating Process: HydraHeadiPad [1419]
Triggered by Thread: 0
Last Exception Backtrace:
0 CoreFoundation 0x18edbc964 __exceptionPreprocess + 164 (NSException.m:249)
1 libobjc.A.dylib 0x18bc99814 objc_exception_throw + 88 (objc-exception.mm:356)
2 CoreFoundation 0x18ee572c0 -[NSObject(NSObject) doesNotRecognizeSelector:] + 384 (NSObject.m:168)
3 UIKitCore 0x195b73358 -[UIResponder doesNotRecognizeSelector:] + 260 (UIResponder.m:848)
4 CoreFoundation 0x18ed3c35c ___forwarding___ + 1472 (NSForwarding.m:3616)
5 CoreFoundation 0x18ed44200 _CF_forwarding_prep_0 + 96 (:-1)
6 HydraHeadiPad 0x102a9aa74 -[StreamFrameViewController viewDidAppear:] + 56 (StreamFrameViewController.m:61)
7 UIKitCore 0x1953b92f4 -[UIViewController _setViewAppearState:isAnimating:] + 876 (UIViewController.m:6905)
8 UIKitCore 0x1953b9f30 -[UIViewController __viewDidAppear:] + 164 (UIViewController.m:7165)
9 UIKitCore 0x1953ba210 -[UIViewController _endAppearanceTransition:] + 212 (UIViewController.m:7255)
10 UIKitCore 0x1952c6844 __48-[UIPresentationController transitionDidFinish:]_block_invoke + 108 (UIPresentationController.m:609)
11 UIKitCore 0x1952c6564 -[UIPresentationController transitionDidFinish:] + 816 (UIPresentationController.m:681)
12 UIKitCore 0x1952cffb4 -[_UICurrentContextPresentationController transitionDidFinish:] + 44 (_UICurrentContextPresentationController.m:74)
13 UIKitCore 0x1952c9e9c __77-[UIPresentationController runTransitionForCurrentStateAnimated:handoffData:]_block_invoke.106 + 344 (UIPresentationController.m:1434)
14 UIKitCore 0x1953d4bb0 -[_UIViewControllerTransitionContext completeTransition:] + 192 (UIViewControllerTransitioning.m:366)
15 UIKitCore 0x1947b6b6c -[_UIAfterCACommitBlock run] + 72 (_UIAfterCACommitQueue.m:137)
16 UIKitCore 0x1947b6aa4 -[_UIAfterCACommitQueue flush] + 168 (_UIAfterCACommitQueue.m:228)
17 libdispatch.dylib 0x1c7a1cadc _dispatch_call_block_and_release + 32 (init.c:1575)
18 libdispatch.dylib 0x1c7a367fc _dispatch_client_callout + 16 (client_callout.mm:85)
19 libdispatch.dylib 0x1c7a53b10 _dispatch_main_queue_drain.cold.5 + 812 (queue.c:8181)
20 libdispatch.dylib 0x1c7a2bec8 _dispatch_main_queue_drain + 180 (queue.c:8162)
21 libdispatch.dylib 0x1c7a2be04 _dispatch_main_queue_callback_4CF + 44 (queue.c:8341)
22 CoreFoundation 0x18ed612b4 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 16 (CFRunLoop.c:1820)
23 CoreFoundation 0x18ed14b3c __CFRunLoopRun + 1944 (CFRunLoop.c:3177)
24 CoreFoundation 0x18ed13a6c _CFRunLoopRunSpecificWithOptions + 532 (CFRunLoop.c:3462)
25 GraphicsServices 0x2332aa498 GSEventRunModal + 120 (GSEvent.c:2049)
26 UIKitCore 0x1947c3df8 -[UIApplication _run] + 792 (UIApplication.m:3904)
27 UIKitCore 0x19476ce54 UIApplicationMain + 336 (UIApplication.m:5579)
28 SwiftUI 0x197a84d20 closure #1 in KitRendererCommon(_:) + 168 (UIKitApp.swift:65)
29 SwiftUI 0x197a818d4 runApp<A>(_:) + 112 (UIKitApp.swift:16)
30 SwiftUI 0x197a813c0 static App.main() + 172 (App.swift:137)
31 HydraHeadiPad 0x102aab164 static HydraHeadiPadApp.$main() + 24 (App.swift:0)
32 HydraHeadiPad 0x102aab164 main + 36
33 dyld 0x18bceee28 start + 7116 (dyldMain.cpp:1477)
Thread 0 name:
Thread 0 Crashed:
0 libsystem_kernel.dylib 0x000000023c4920cc __pthread_kill + 8 (:-1)
1 libsystem_pthread.dylib 0x00000001eb7b3810 pthread_kill + 268 (pthread.c:1721)
2 libsystem_c.dylib 0x000000019a698f64 abort + 124 (abort.c:122)
3 libc++abi.dylib 0x000000018bd9c808 __abort_message + 132 (abort_message.cpp:66)
4 libc++abi.dylib 0x000000018bd8b484 demangling_terminate_handler() + 304 (cxa_default_handlers.cpp:76)
5 libobjc.A.dylib 0x000000018bc9bf78 _objc_terminate() + 156 (objc-exception.mm:496)
6 libc++abi.dylib 0x000000018bd9bbdc std::__terminate(void (*)()) + 16 (cxa_handlers.cpp:59)
7 libc++abi.dylib 0x000000018bd9f314 __cxxabiv1::failed_throw(__cxxabiv1::__cxa_exception*) + 88 (cxa_exception.cpp:152)
8 libc++abi.dylib 0x000000018bd9f2bc __cxa_throw + 92 (cxa_exception.cpp:299)
9 libobjc.A.dylib 0x000000018bc9997c objc_exception_throw + 448 (objc-exception.mm:385)
10 CoreFoundation 0x000000018ee572c0 -[NSObject(NSObject) doesNotRecognizeSelector:] + 384 (NSObject.m:168)
11 UIKitCore 0x0000000195b73358 -[UIResponder doesNotRecognizeSelector:] + 260 (UIResponder.m:848)
12 CoreFoundation 0x000000018ed3c35c ___forwarding___ + 1472 (NSForwarding.m:3616)
13 CoreFoundation 0x000000018ed44200 _CF_forwarding_prep_0 + 96 (:-1)
14 HydraHeadiPad 0x0000000102a9aa74 -[StreamFrameViewController viewDidAppear:] + 56 (StreamFrameViewController.m:61)
15 UIKitCore 0x00000001953b92f4 -[UIViewController _setViewAppearState:isAnimating:] + 876 (UIViewController.m:6905)
16 UIKitCore 0x00000001953b9f30 -[UIViewController __viewDidAppear:] + 164 (UIViewController.m:7165)
17 UIKitCore 0x00000001953ba210 -[UIViewController _endAppearanceTransition:] + 212 (UIViewController.m:7255)
18 UIKitCore 0x00000001952c6844 __48-[UIPresentationController transitionDidFinish:]_block_invoke + 108 (UIPresentationController.m:609)
19 UIKitCore 0x00000001952c6564 -[UIPresentationController transitionDidFinish:] + 816 (UIPresentationController.m:681)
20 UIKitCore 0x00000001952cffb4 -[_UICurrentContextPresentationController transitionDidFinish:] + 44 (_UICurrentContextPresentationController.m:74)
21 UIKitCore 0x00000001952c9e9c __77-[UIPresentationController runTransitionForCurrentStateAnimated:handoffData:]_block_invoke.106 + 344 (UIPresentationController.m:1434)
22 UIKitCore 0x00000001953d4bb0 -[_UIViewControllerTransitionContext completeTransition:] + 192 (UIViewControllerTransitioning.m:366)
23 UIKitCore 0x00000001947b6b6c -[_UIAfterCACommitBlock run] + 72 (_UIAfterCACommitQueue.m:137)
24 UIKitCore 0x00000001947b6aa4 -[_UIAfterCACommitQueue flush] + 168 (_UIAfterCACommitQueue.m:228)
25 libdispatch.dylib 0x00000001c7a1cadc _dispatch_call_block_and_release + 32 (init.c:1575)
26 libdispatch.dylib 0x00000001c7a367fc _dispatch_client_callout + 16 (client_callout.mm:85)
27 libdispatch.dylib 0x00000001c7a53b10 _dispatch_main_queue_drain.cold.5 + 812 (queue.c:8181)
28 libdispatch.dylib 0x00000001c7a2bec8 _dispatch_main_queue_drain + 180 (queue.c:8162)
29 libdispatch.dylib 0x00000001c7a2be04 _dispatch_main_queue_callback_4CF + 44 (queue.c:8341)
30 CoreFoundation 0x000000018ed612b4 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 16 (CFRunLoop.c:1820)
31 CoreFoundation 0x000000018ed14b3c __CFRunLoopRun + 1944 (CFRunLoop.c:3177)
32 CoreFoundation 0x000000018ed13a6c _CFRunLoopRunSpecificWithOptions + 532 (CFRunLoop.c:3462)
33 GraphicsServices 0x00000002332aa498 GSEventRunModal + 120 (GSEvent.c:2049)
34 UIKitCore 0x00000001947c3df8 -[UIApplication _run] + 792 (UIApplication.m:3904)
35 UIKitCore 0x000000019476ce54 UIApplicationMain + 336 (UIApplication.m:5579)
36 SwiftUI 0x0000000197a84d20 closure #1 in KitRendererCommon(_:) + 168 (UIKitApp.swift:65)
37 SwiftUI 0x0000000197a818d4 runApp<A>(_:) + 112 (UIKitApp.swift:16)
38 SwiftUI 0x0000000197a813c0 static App.main() + 172 (App.swift:137)
39 HydraHeadiPad 0x0000000102aab164 static HydraHeadiPadApp.$main() + 24 (App.swift:0)
40 HydraHeadiPad 0x0000000102aab164 main + 36
41 dyld 0x000000018bceee28 start + 7116 (dyldMain.cpp:1477)
Thread 1 name:
Thread 1:
0 libdispatch.dylib 0x00000001c7a4cb64 _dispatch_data_dispose + 140 (data.c:265)
1 libxpc.dylib 0x00000001a30fb84c -[OS_xpc_object dealloc] + 28 (object.m:26)
2 libxpc.dylib 0x00000001a30e388c _xpc_dictionary_node_free + 80 (dictionary.c:95)
3 libxpc.dylib 0x00000001a30e09e4 _xpc_dictionary_dispose + 48 (dictionary.c:1299)
4 libxpc.dylib 0x00000001a30fb84c -[OS_xpc_object dealloc] + 28 (object.m:26)
5 Foundation 0x000000018cda2420 -[NSXPCConnection _sendInvocation:orArguments:count:methodSignature:selector:withProxy:] + 2224 (NSXPCConnection.m:1705)
6 CoreFoundation 0x000000018ed3c1cc ___forwarding___ + 1072 (NSForwarding.m:3650)
7 CoreFoundation 0x000000018ed44200 _CF_forwarding_prep_0 + 96 (:-1)
8 GameController 0x00000001df33cc58 __70-[_GCControllerManagerAppClient(ControllerService) refreshControllers]_block_invoke + 104 (GCControllerManagerApp.m:934)
9 libsystem_trace.dylib 0x00000001b3c35b34 _os_activity_initiate_impl + 64 (activity.c:137)
10 GameController 0x00000001df33cbe4 -[_GCControllerManagerAppClient(ControllerService) refreshControllers] + 116 (GCControllerManagerApp.m:934)
11 GameController 0x00000001df33a244 __56-[_GCControllerManagerAppClient _resumeDaemonConnection]_block_invoke + 76 (GCControllerManagerApp.m:288)
12 CoreFoundation 0x000000018ed3c6c4 __invoking___ + 148 (:-1)
13 CoreFoundation 0x000000018ed3c550 -[NSInvocation invoke] + 424 (NSForwarding.m:3411)
14 Foundation 0x000000018c359a10 <deduplicated_symbol> + 16 (:-1)
15 Foundation 0x000000018cd9eb68 -[NSXPCConnection _decodeAndInvokeReplyBlockWithEvent:sequence:replyInfo:] + 528 (NSXPCConnection.m:314)
16 Foundation 0x000000018cda28d4 __88-[NSXPCConnection _sendInvocation:orArguments:count:methodSignature:selector:withProxy:]_block_invoke_5 + 188 (NSXPCConnection.m:1658)
17 libxpc.dylib 0x00000001a30eae90 _xpc_connection_reply_callout + 124 (serializer.c:119)
18 libxpc.dylib 0x00000001a30dc584 _xpc_connection_call_reply_async + 96 (connection.c:940)
19 libdispatch.dylib 0x00000001c7a3682c <deduplicated_symbol> + 16 (:-1)
20 libdispatch.dylib 0x00000001c7a3a820 _dispatch_mach_msg_async_reply_invoke + 340 (mach.c:3111)
21 libdispatch.dylib 0x00000001c7a27288 _dispatch_workloop_invoke + 1612 (queue.c:4761)
22 libdispatch.dylib 0x00000001c7a303ec _dispatch_root_queue_drain_deferred_wlh + 292 (queue.c:7265)
23 libdispatch.dylib 0x00000001c7a2fce4 _dispatch_workloop_worker_thread + 692 (queue.c:6859)
24 libsystem_pthread.dylib 0x00000001eb7ad3b8 _pthread_wqthread + 292 (pthread.c:2696)
25 libsystem_pthread.dylib 0x00000001eb7ac8c0 start_wqthread + 8 (:-1)
Thread 2:
Thread 3:
Thread 4:
Thread 5:
Thread 6:
Thread 7:
Thread 8 name:
Thread 8:
0 libsystem_kernel.dylib 0x000000023c487cd4 mach_msg2_trap + 8 (:-1)
1 libsystem_kernel.dylib 0x000000023c48b2f8 mach_msg2_internal + 76 (mach_msg.c:201)
2 libsystem_kernel.dylib 0x000000023c48b214 mach_msg_overwrite + 428 (mach_msg.c:0)
3 libsystem_kernel.dylib 0x000000023c48b05c mach_msg + 24 (mach_msg.c:323)
4 CoreFoundation 0x000000018ed3d868 __CFRunLoopServiceMachPort + 160 (CFRunLoop.c:2650)
5 CoreFoundation 0x000000018ed14848 __CFRunLoopRun + 1188 (CFRunLoop.c:3035)
6 CoreFoundation 0x000000018ed13a6c _CFRunLoopRunSpecificWithOptions + 532 (CFRunLoop.c:3462)
7 Foundation 0x000000018ccd3f54 -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 212 (NSRunLoop.m:375)
8 Foundation 0x000000018ccd412c -[NSRunLoop(NSRunLoop) runUntilDate:] + 64 (NSRunLoop.m:422)
9 UIKitCore 0x0000000194799094 -[UIEventFetcher threadMain] + 408 (UIEventFetcher.m:1333)
10 Foundation 0x000000018c39321c __NSThread__start__ + 732 (NSThread.m:997)
11 libsystem_pthread.dylib 0x00000001eb7b044c _pthread_start + 136 (pthread.c:931)
12 libsystem_pthread.dylib 0x00000001eb7ac8cc thread_start + 8 (:-1)
Thread 9:
Thread 10 name:
Thread 10:
0 libsystem_kernel.dylib 0x000000023c487c50 semaphore_wait_trap + 8 (:-1)
1 libdispatch.dylib 0x00000001c7a1e910 _dispatch_sema4_wait + 28 (lock.c:139)
2 libdispatch.dylib 0x00000001c7a1eec0 _dispatch_semaphore_wait_slow + 132 (semaphore.c:132)
3 HydraHeadiPad 0x0000000102a87cd0 -[HttpManager executeRequestSynchronously:] + 384 (HttpManager.m:147)
4 HydraHeadiPad 0x0000000102a9cb80 -[StreamManager main] + 256 (StreamManager.m:47)
5 Foundation 0x000000018c349074 __NSOPERATION_IS_INVOKING_MAIN__ + 16 (NSOperation.m:2199)
6 Foundation 0x000000018c348b14 -[NSOperation start] + 640 (NSOperation.m:1407)
7 Foundation 0x000000018c348edc __NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 16 (NSOperation.m:2230)
8 Foundation 0x000000018c348798 __NSOQSchedule_f + 164 (NSOperation.m:2241)
9 libdispatch.dylib 0x00000001c7a2c450 _dispatch_block_async_invoke2 + 148 (queue.c:598)
10 libdispatch.dylib 0x00000001c7a367fc _dispatch_client_callout + 16 (client_callout.mm:85)
11 libdispatch.dylib 0x00000001c7a21664 _dispatch_continuation_pop + 596 (queue.c:349)
12 libdispatch.dylib 0x00000001c7a20cd8 _dispatch_async_redirect_invoke + 580 (queue.c:873)
13 libdispatch.dylib 0x00000001c7a2ef48 _dispatch_root_queue_drain + 364 (queue.c:7409)
14 libdispatch.dylib 0x00000001c7a2f6fc _dispatch_worker_thread2 + 180 (queue.c:7487)
15 libsystem_pthread.dylib 0x00000001eb7ad37c _pthread_wqthread + 232 (pthread.c:2709)
16 libsystem_pthread.dylib 0x00000001eb7ac8c0 start_wqthread + 8 (:-1)
Thread 11 name:
Thread 11:
0 libsystem_kernel.dylib 0x000000023c487cd4 mach_msg2_trap + 8 (:-1)
1 libsystem_kernel.dylib 0x000000023c48b2f8 mach_msg2_internal + 76 (mach_msg.c:201)
2 libsystem_kernel.dylib 0x000000023c48b214 mach_msg_overwrite + 428 (mach_msg.c:0)
3 libsystem_kernel.dylib 0x000000023c48b05c mach_msg + 24 (mach_msg.c:323)
4 CoreFoundation 0x000000018ed3d868 __CFRunLoopServiceMachPort + 160 (CFRunLoop.c:2650)
5 CoreFoundation 0x000000018ed14848 __CFRunLoopRun + 1188 (CFRunLoop.c:3035)
6 CoreFoundation 0x000000018ed13a6c _CFRunLoopRunSpecificWithOptions + 532 (CFRunLoop.c:3462)
7 CFNetwork 0x00000001a3c65c10 +[__CFN_CoreSchedulingSetRunnable _run:] + 416 (CoreSchedulingSet.mm:1473)
8 Foundation 0x000000018c39321c __NSThread__start__ + 732 (NSThread.m:997)
9 libsystem_pthread.dylib 0x00000001eb7b044c _pthread_start + 136 (pthread.c:931)
10 libsystem_pthread.dylib 0x00000001eb7ac8cc thread_start + 8 (:-1)
Thread 0 crashed with ARM Thread State (64-bit):
x0: 0x0000000000000000 x1: 0x0000000000000000 x2: 0x0000000000000000 x3: 0x0000000000000000
x4: 0x000000018bda0f43 x5: 0x000000016d388a10 x6: 0x000000000000006e x7: 0xfffff0003ffff800
x8: 0x5611bfd5f780f1c6 x9: 0x5611bfd40fb413c6 x10: 0x0000000000000002 x11: 0x0000010000000000
x12: 0x00000000fffffffd x13: 0x0000000000000000 x14: 0x0000000000000000 x15: 0x0000000000000000
x16: 0x0000000000000148 x17: 0x00000001f834e200 x18: 0x0000000000000000 x19: 0x0000000000000006
x20: 0x0000000000000103 x21: 0x00000001f834e2e0 x22: 0x00000001f52b8000 x23: 0x0000000000000001
x24: 0x0000000000000001 x25: 0x0000000000000068 x26: 0x000000016d389ae0 x27: 0x00000001f833cd30
x28: 0x00000001f5440000 fp: 0x000000016d388980 lr: 0x00000001eb7b3810
sp: 0x000000016d388960 pc: 0x000000023c4920cc cpsr: 0x40000000
esr: 0x56000080 (Syscall)
Binary Images:
0x102a74000 - 0x102d23fff HydraHeadiPad arm64 <500c0e0f490f357b8ee59409fb757fb3> /var/containers/Bundle/Application/74DFDB54-DBE3-484F-AD22-3B39156E83F8/HydraHeadiPad.app/HydraHeadiPad
0x102f4c000 - 0x102f57fff libobjc-trampolines.dylib arm64e <1954b963897d321f88be880ecef5b408> /private/preboot/Cryptexes/OS/usr/lib/libobjc-trampolines.dylib
0x18bc68000 - 0x18bcb9b5f libobjc.A.dylib arm64e <4358daf977583542a1e19f185534a911> /usr/lib/libobjc.A.dylib
0x18bcea000 - 0x18bd89347 dyld arm64e <7631b298c24e3532b62500a1ad73c1fd> /usr/lib/dyld
0x18bd8a000 - 0x18bda46c7 libc++abi.dylib arm64e <a741ff8f8ad1315780ba476d6d990c23> /usr/lib/libc++abi.dylib
0x18c331000 - 0x18d177c9f Foundation arm64e <4c3912d2e14a3a21926b54bef625be89> /System/Library/Frameworks/Foundation.framework/Foundation
0x18ecf7000 - 0x18f27d73f CoreFoundation arm64e <d52bceeee890347c84611537154e22d9> /System/Library/Frameworks/CoreFoundation.framework/CoreFoundation
0x194726000 - 0x196b859bf UIKitCore arm64e <a70d8d96f3a53099901127eeb49d7be8> /System/Library/PrivateFrameworks/UIKitCore.framework/UIKitCore
0x197a53000 - 0x198cd4fdf SwiftUI arm64e <b78443e4291f3ffd931bde278e9ec5b8> /System/Library/Frameworks/SwiftUI.framework/SwiftUI
0x19a621000 - 0x19a6a15af libsystem_c.dylib arm64e <61a33aa9d6683b35a859b6925c4047b9> /usr/lib/system/libsystem_c.dylib
0x1a30c9000 - 0x1a311b07f libxpc.dylib arm64e <26e3f9d775bb3384a2bf2628f1dbb2bc> /usr/lib/system/libxpc.dylib
0x1a3a1d000 - 0x1a3dd38bf CFNetwork arm64e <ac6cb88437403320999436594af6ad73> /System/Library/Frameworks/CFNetwork.framework/CFNetwork
0x1b3c2f000 - 0x1b3c4f31f libsystem_trace.dylib arm64e <d1d02aad393939dfbb569ad956d67e22> /usr/lib/system/libsystem_trace.dylib
0x1c7a1b000 - 0x1c7a6121f libdispatch.dylib arm64e <904d48a3d99e3962bfa9c3dfb66bba83> /usr/lib/system/libdispatch.dylib
0x1df2c3000 - 0x1df43647f GameController arm64e <aee2801276cb3931af8dff15ebd56dc4> /System/Library/Frameworks/GameController.framework/GameController
0x1eb7ac000 - 0x1eb7b845f libsystem_pthread.dylib arm64e <4f94107b94d23e888542f5403c581b50> /usr/lib/system/libsystem_pthread.dylib
0x2332a9000 - 0x2332b17ff GraphicsServices arm64e <12a401ff966436029f17f3047446e62b> /System/Library/PrivateFrameworks/GraphicsServices.framework/GraphicsServices
0x23c487000 - 0x23c4c1d2b libsystem_kernel.dylib arm64e <8d8301292cbe32a9b61ece493eecb399> /usr/lib/system/libsystem_kernel.dylib
EOF