/in/foo.c:1:1: warning: data definition has no type or storage class
 s = input().split()
 ^
/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]
 s = input().split()
     ^~~~~
/in/foo.c:1:12: error: request for member 'split' in something not a structure or union
 s = input().split()
            ^
/in/foo.c:2:1: error: expected ',' or ';' before 'm'
 m = max(map(len, s))
 ^