foo.c:1:1: warning: data definition has no type or storage class
 s = str(input())
 ^
foo.c:1:1: warning: type defaults to 'int' in declaration of 's' [-Wimplicit-int]
foo.c:1:5: warning: implicit declaration of function 'str' [-Wimplicit-function-declaration]
 s = str(input())
     ^~~
foo.c:1:9: warning: implicit declaration of function 'input' [-Wimplicit-function-declaration]
 s = str(input())
         ^~~~~
foo.c:1:5: error: initializer element is not constant
 s = str(input())
     ^~~
foo.c:2:1: error: expected ',' or ';' before 'x'
 x = len(s)
 ^