Language: C

中間試験、期末試験のいずれかを欠席した場合成績は F。
中間試験と期末試験の合計点数が 80 以上ならば成績は A 。
中間試験と期末試験の合計点数が 65 以上 80 未満ならば成績は B。
中間試験と期末試験の合計点数が 50 以上 65 未満ならば成績は C。
中間試験と期末試験の合計点数が 30 以上 50 未満ならば成績は D。 ただし、再試験の点数が 50 以上ならば成績は C。
中間試験と期末試験の合計点数が 30 未満ならば成績は F。

#include <stdio.h>

int main(){

int r,m,f;

while(1){

 scanf("%d%d%d",&r,&m,&f);
 if(r==-1&&m==-1&&f==-1)break;
 if(r==-1||m==-1)printf("F\n");
 else if((r+m)>=80)printf("A\n");
 else if((r+m)>=65)printf("B\n");
 else if((r+m)>=30){
  if(f>=50)printf("C\n");
  else printf("D\n");
 }else prinf("F\n");

}

return 0;
}

Compiler output:
main.c:1:9: error: stray '\343' in program
    1 | <U+4E2D><U+9593><U+8A66><U+9A13><U+3001><U+671F><U+672B><U+8A66><U+9A13><U+306E><U+3044><U+305A><U+308C><U+304B><U+3092><U+6B20><U+5E2D><U+3057><U+305F><U+5834><U+5408><U+6210><U+7E3E><U+306F> F<U+3002>
      |                                 ^~~~~~~~
main.c:1:1: error: unknown type name '\U00004e2d\U00009593\U00008a66\U00009a13'
    1 | 中間試験、期末試験のいずれかを欠席した場合成績は F。
      | ^~~~~~~~
main.c:1:50: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'F'
    1 | 中間試験、期末試験のいずれかを欠席した場合成績は F。
      |                                                  ^
main.c:1:51: error: stray '\343' in program
    1 | <U+4E2D><U+9593><U+8A66><U+9A13><U+3001><U+671F><U+672B><U+8A66><U+9A13><U+306E><U+3044><U+305A><U+308C><U+304B><U+3092><U+6B20><U+5E2D><U+3057><U+305F><U+5834><U+5408><U+6210><U+7E3E><U+306F> F<U+3002>
      |                                                                                                                                                                                                   ^~~~~~~~
main.c:1:50: error: unknown type name 'F'
    1 | 中間試験、期末試験のいずれかを欠席した場合成績は F。
      |                                                  ^
main.c:2:54: error: stray '\343' in program
    2 | <U+4E2D><U+9593><U+8A66><U+9A13><U+3068><U+671F><U+672B><U+8A66><U+9A13><U+306E><U+5408><U+8A08><U+70B9><U+6570><U+304C> 80 <U+4EE5><U+4E0A><U+306A><U+3089><U+3070><U+6210><U+7E3E><U+306F> A <U+3002>
      |                                                                                                                                                                                                ^~~~~~~~
main.c:3:61: error: stray '\343' in program
    3 | <U+4E2D><U+9593><U+8A66><U+9A13><U+3068><U+671F><U+672B><U+8A66><U+9A13><U+306E><U+5408><U+8A08><U+70B9><U+6570><U+304C> 65 <U+4EE5><U+4E0A> 80 <U+672A><U+6E80><U+306A><U+3089><U+3070><U+6210><U+7E3E><U+306F> B<U+3002>
      |                                                                                                                                                                                                                   ^~~~~~~~
main.c:4:61: error: stray '\343' in program
    4 | <U+4E2D><U+9593><U+8A66><U+9A13><U+3068><U+671F><U+672B><U+8A66><U+9A13><U+306E><U+5408><U+8A08><U+70B9><U+6570><U+304C> 50 <U+4EE5><U+4E0A> 65 <U+672A><U+6E80><U+306A><U+3089><U+3070><U+6210><U+7E3E><U+306F> C<U+3002>
      |                                                                                                                                                                                                                   ^~~~~~~~
main.c:5:61: error: stray '\343' in program
    5 | <U+4E2D><U+9593><U+8A66><U+9A13><U+3068><U+671F><U+672B><U+8A66><U+9A13><U+306E><U+5408><U+8A08><U+70B9><U+6570><U+304C> 30 <U+4EE5><U+4E0A> 50 <U+672A><U+6E80><U+306A><U+3089><U+3070><U+6210><U+7E3E><U+306F> D<U+3002> <U+305F><U+3060><U+3057><U+3001><U+518D><U+8A66><U+9A13><U+306E><U+70B9><U+6570><U+304C> 50 <U+4EE5><U+4E0A><U+306A><U+3089><U+3070><U+6210><U+7E3E><U+306F> C<U+3002>
      |                                                                                                                                                                                                                   ^~~~~~~~
main.c:5:70: error: stray '\343' in program
    5 | <U+4E2D><U+9593><U+8A66><U+9A13><U+3068><U+671F><U+672B><U+8A66><U+9A13><U+306E><U+5408><U+8A08><U+70B9><U+6570><U+304C> 30 <U+4EE5><U+4E0A> 50 <U+672A><U+6E80><U+306A><U+3089><U+3070><U+6210><U+7E3E><U+306F> D<U+3002> <U+305F><U+3060><U+3057><U+3001><U+518D><U+8A66><U+9A13><U+306E><U+70B9><U+6570><U+304C> 50 <U+4EE5><U+4E0A><U+306A><U+3089><U+3070><U+6210><U+7E3E><U+306F> C<U+3002>
      |                                                                                                                                                                                                                                                    ^~~~~~~~
main.c:5:108: error: stray '\343' in program
    5 | <U+4E2D><U+9593><U+8A66><U+9A13><U+3068><U+671F><U+672B><U+8A66><U+9A13><U+306E><U+5408><U+8A08><U+70B9><U+6570><U+304C> 30 <U+4EE5><U+4E0A> 50 <U+672A><U+6E80><U+306A><U+3089><U+3070><U+6210><U+7E3E><U+306F> D<U+3002> <U+305F><U+3060><U+3057><U+3001><U+518D><U+8A66><U+9A13><U+306E><U+70B9><U+6570><U+304C> 50 <U+4EE5><U+4E0A><U+306A><U+3089><U+3070><U+6210><U+7E3E><U+306F> C<U+3002>
      |                                                                                                                                                                                                                                                                                                                                                                                          ^~~~~~~~
main.c:6:53: error: stray '\343' in program
    6 | <U+4E2D><U+9593><U+8A66><U+9A13><U+3068><U+671F><U+672B><U+8A66><U+9A13><U+306E><U+5408><U+8A08><U+70B9><U+6570><U+304C> 30 <U+672A><U+6E80><U+306A><U+3089><U+3070><U+6210><U+7E3E><U+306F> F<U+3002>
      |                                                                                                                                                                                               ^~~~~~~~
In file included from /usr/include/stdio.h:47,
                 from main.c:8:
/usr/include/x86_64-linux-gnu/bits/types/cookie_io_functions_t.h:28:43: error: unknown type name 'size_t'
   28 |                                           size_t __nbytes);
      |                                           ^~~~~~
/usr/include/x86_64-linux-gnu/bits/types/cookie_io_functions_t.h:1:1: note: 'size_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
  +++ |+#include <stddef.h>
    1 | /* Copyright (C) 1991-2025 Free Software Foundation, Inc.
/usr/include/x86_64-linux-gnu/bits/types/cookie_io_functions_t.h:37:44: error: unknown type name 'size_t'
   37 |                                            size_t __nbytes);
      |                                            ^~~~~~
/usr/include/x86_64-linux-gnu/bits/types/cookie_io_functions_t.h:37:44: note: 'size_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
/usr/include/x86_64-linux-gnu/bits/types/cookie_io_functions_t.h:57:3: error: unknown type name 'cookie_read_function_t'; did you mean 'cookie_seek_function_t'?
   57 |   cookie_read_function_t *read;         /* Read bytes.  */
      |   ^~~~~~~~~~~~~~~~~~~~~~
      |   cookie_seek_function_t
/usr/include/x86_64-linux-gnu/bits/types/cookie_io_functions_t.h:58:3: error: unknown type name 'cookie_write_function_t'; did you mean 'cookie_close_function_t'?
   58 |   cookie_write_function_t *write;       /* Write bytes.  */
      |   ^~~~~~~~~~~~~~~~~~~~~~~
      |   cookie_close_function_t
/usr/include/stdio.h:314:35: error: unknown type name 'size_t'
  314 | extern FILE *fmemopen (void *__s, size_t __len, const char *__modes)
      |                                   ^~~~~~
/usr/include/stdio.h:130:1: note: 'size_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
  129 | #include <bits/stdio_lim.h>
  +++ |+#include <stddef.h>
  130 | 
/usr/include/stdio.h:320:47: error: unknown type name 'size_t'
  320 | extern FILE *open_memstream (char **__bufloc, size_t *__sizeloc) __THROW
      |                                               ^~~~~~
/usr/include/stdio.h:320:47: note: 'size_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
/usr/include/stdio.h:340:34: error: unknown type name 'size_t'
  340 |                     int __modes, size_t __n) __THROW __nonnull ((1));
      |                                  ^~~~~~
/usr/include/stdio.h:340:34: note: 'size_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
/usr/include/stdio.h:346:24: error: unknown type name 'size_t'
  346 |                        size_t __size) __THROW __nonnull ((1));
      |                        ^~~~~~
/usr/include/stdio.h:346:24: note: 'size_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
/usr/include/stdio.h:385:44: error: unknown type name 'size_t'
  385 | extern int snprintf (char *__restrict __s, size_t __maxlen,
      |                                            ^~~~~~
/usr/include/stdio.h:385:44: note: 'size_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
/usr/include/stdio.h:389:45: error: unknown type name 'size_t'
  389 | extern int vsnprintf (char *__restrict __s, size_t __maxlen,
      |                                             ^~~~~~
/usr/include/stdio.h:389:45: note: 'size_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
/usr/include/stdio.h:690:30: error: unknown type name 'size_t'
  690 |                              size_t *__restrict __n, int __delimiter,
      |                              ^~~~~~
/usr/include/stdio.h:690:30: note: 'size_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
/usr/include/stdio.h:693:28: error: unknown type name 'size_t'
  693 |                            size_t *__restrict __n, int __delimiter,
      |                            ^~~~~~
/usr/include/stdio.h:693:28: note: 'size_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
/usr/include/stdio.h:698:27: error: unknown type name 'size_t'
  698 |                           size_t *__restrict __n,
      |                           ^~~~~~
/usr/include/stdio.h:698:27: note: 'size_t' is defined in header '<stddef.h>'; this is probably fixable by adding '#include <stddef.h>'
/usr/include/stdio.h:728:8: error: unknown type name 'size_t'
  728 | extern size_t fread (void *__restrict __ptr, size_t __size,
      |        ^~~~~~
/usr/include/stdio.h:728:8: note: 'size_t' is defined in header '<stdd