报错信息：

In file included from /nix/gcc/include/c++/13.3.0/x86_64-unknown-linux-gnu/bits/stdc++.h:97,
                 from foo.cc:1:
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:40:9: error: ‘_Atomic’ does not name a type
   40 | typedef _Atomic _Bool atomic_bool;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:41:9: error: ‘_Atomic’ does not name a type
   41 | typedef _Atomic char atomic_char;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:42:9: error: ‘_Atomic’ does not name a type
   42 | typedef _Atomic signed char atomic_schar;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:43:9: error: ‘_Atomic’ does not name a type
   43 | typedef _Atomic unsigned char atomic_uchar;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:44:9: error: ‘_Atomic’ does not name a type
   44 | typedef _Atomic short atomic_short;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:45:9: error: ‘_Atomic’ does not name a type
   45 | typedef _Atomic unsigned short atomic_ushort;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:46:9: error: ‘_Atomic’ does not name a type
   46 | typedef _Atomic int atomic_int;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:47:9: error: ‘_Atomic’ does not name a type
   47 | typedef _Atomic unsigned int atomic_uint;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:48:9: error: ‘_Atomic’ does not name a type
   48 | typedef _Atomic long atomic_long;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:49:9: error: ‘_Atomic’ does not name a type
   49 | typedef _Atomic unsigned long atomic_ulong;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:50:9: error: ‘_Atomic’ does not name a type
   50 | typedef _Atomic long long atomic_llong;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:51:9: error: ‘_Atomic’ does not name a type
   51 | typedef _Atomic unsigned long long atomic_ullong;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:53:9: error: ‘_Atomic’ does not name a type
   53 | typedef _Atomic __CHAR8_TYPE__ atomic_char8_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:55:9: error: ‘_Atomic’ does not name a type
   55 | typedef _Atomic __CHAR16_TYPE__ atomic_char16_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:56:9: error: ‘_Atomic’ does not name a type
   56 | typedef _Atomic __CHAR32_TYPE__ atomic_char32_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:57:9: error: ‘_Atomic’ does not name a type
   57 | typedef _Atomic __WCHAR_TYPE__ atomic_wchar_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:58:9: error: ‘_Atomic’ does not name a type
   58 | typedef _Atomic __INT_LEAST8_TYPE__ atomic_int_least8_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:59:9: error: ‘_Atomic’ does not name a type
   59 | typedef _Atomic __UINT_LEAST8_TYPE__ atomic_uint_least8_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:60:9: error: ‘_Atomic’ does not name a type
   60 | typedef _Atomic __INT_LEAST16_TYPE__ atomic_int_least16_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:61:9: error: ‘_Atomic’ does not name a type
   61 | typedef _Atomic __UINT_LEAST16_TYPE__ atomic_uint_least16_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:62:9: error: ‘_Atomic’ does not name a type
   62 | typedef _Atomic __INT_LEAST32_TYPE__ atomic_int_least32_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:63:9: error: ‘_Atomic’ does not name a type
   63 | typedef _Atomic __UINT_LEAST32_TYPE__ atomic_uint_least32_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:64:9: error: ‘_Atomic’ does not name a type
   64 | typedef _Atomic __INT_LEAST64_TYPE__ atomic_int_least64_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:65:9: error: ‘_Atomic’ does not name a type
   65 | typedef _Atomic __UINT_LEAST64_TYPE__ atomic_uint_least64_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:66:9: error: ‘_Atomic’ does not name a type
   66 | typedef _Atomic __INT_FAST8_TYPE__ atomic_int_fast8_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:67:9: error: ‘_Atomic’ does not name a type
   67 | typedef _Atomic __UINT_FAST8_TYPE__ atomic_uint_fast8_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:68:9: error: ‘_Atomic’ does not name a type
   68 | typedef _Atomic __INT_FAST16_TYPE__ atomic_int_fast16_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:69:9: error: ‘_Atomic’ does not name a type
   69 | typedef _Atomic __UINT_FAST16_TYPE__ atomic_uint_fast16_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:70:9: error: ‘_Atomic’ does not name a type
   70 | typedef _Atomic __INT_FAST32_TYPE__ atomic_int_fast32_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:71:9: error: ‘_Atomic’ does not name a type
   71 | typedef _Atomic __UINT_FAST32_TYPE__ atomic_uint_fast32_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:72:9: error: ‘_Atomic’ does not name a type
   72 | typedef _Atomic __INT_FAST64_TYPE__ atomic_int_fast64_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:73:9: error: ‘_Atomic’ does not name a type
   73 | typedef _Atomic __UINT_FAST64_TYPE__ atomic_uint_fast64_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:74:9: error: ‘_Atomic’ does not name a type
   74 | typedef _Atomic __INTPTR_TYPE__ atomic_intptr_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:75:9: error: ‘_Atomic’ does not name a type
   75 | typedef _Atomic __UINTPTR_TYPE__ atomic_uintptr_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:76:9: error: ‘_Atomic’ does not name a type
   76 | typedef _Atomic __SIZE_TYPE__ atomic_size_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:77:9: error: ‘_Atomic’ does not name a type
   77 | typedef _Atomic __PTRDIFF_TYPE__ atomic_ptrdiff_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:78:9: error: ‘_Atomic’ does not name a type
   78 | typedef _Atomic __INTMAX_TYPE__ atomic_intmax_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:79:9: error: ‘_Atomic’ does not name a type
   79 | typedef _Atomic __UINTMAX_TYPE__ atomic_uintmax_t;
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:226:9: error: ‘_Atomic’ does not name a type
  226 | typedef _Atomic struct
      |         ^~~~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:233:3: error: ‘atomic_flag’ does not name a type; did you mean ‘atomic_load’?
  233 | } atomic_flag;
      |   ^~~~~~~~~~~
      |   atomic_load
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:238:8: error: ‘_Bool’ does not name a type
  238 | extern _Bool atomic_flag_test_and_set (volatile atomic_flag *);
      |        ^~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:241:8: error: ‘_Bool’ does not name a type
  241 | extern _Bool atomic_flag_test_and_set_explicit (volatile atomic_flag *,
      |        ^~~~~
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:246:41: error: ‘atomic_flag’ does not name a type; did you mean ‘atomic_load’?
  246 | extern void atomic_flag_clear (volatile atomic_flag *);
      |                                         ^~~~~~~~~~~
      |                                         atomic_load
/nix/gcc/lib/gcc/x86_64-unknown-linux-gnu/13.3.0/include/stdatomic.h:248:50: error: ‘atomic_flag’ does not name a type; did you mean ‘atomic_load’?
  248 | extern void atomic_flag_clear_explicit (volatile atomic_flag *, memory_order);
      |                                                  ^~~~~~~~~~~
      |                                                  atomic_load

#include<bits/stdc++.h>
using namespace std;
int a,b;
signed main(){
    cin>>a>>b;
    cout<<a+b;
    return 0;
}

@WHO KNOW 啊