/in/foo.c:3:1: warning: data definition has no type or storage class
 a = int(input())
 ^
/in/foo.c:3:1: warning: type defaults to 'int' in declaration of 'a' [-Wimplicit-int]
/in/foo.c:3:5: error: expected expression before 'int'
 a = int(input())
     ^~~