/in/foo.c:1:1: warning: data definition has no type or storage class
    1 | input_str = input()
      | ^~~~~~~~~
/in/foo.c:1:1: warning: type defaults to 'int' in declaration of 'input_str' [-Wimplicit-int]
/in/foo.c:1:13: warning: implicit declaration of function 'input' [-Wimplicit-function-declaration]
    1 | input_str = input()
      |             ^~~~~
/in/foo.c:1:13: error: initializer element is not constant
/in/foo.c:2:1: error: expected ',' or ';' before 'data'
    2 | data = input_str.split(',')
      | ^~~~