/in/foo.c:1:1: warning: data definition has no type or storage class
    1 | s = input()
      | ^
/in/foo.c:1:1: warning: type defaults to 'int' in declaration of 's' [-Wimplicit-int]
/in/foo.c:1:5: warning: implicit declaration of function 'input' [-Wimplicit-function-declaration]
    1 | s = input()
      |     ^~~~~
/in/foo.c:1:5: error: initializer element is not constant
/in/foo.c:2:1: error: expected ',' or ';' before '_s'
    2 | _s = s[::-1]
      | ^~
/in/foo.c:4:12: warning: character constant too long for its type
    4 |     print(f'{s}是回文数')
      |            ^~~~~~~~~~~~~
/in/foo.c:6:12: warning: character constant too long for its type
    6 |     print(f'{s}不是回文数')
      |            ^~~~~~~~~~~~~~~