src.c:1:5: error: initializer element is not constant
a = input();
^
src.c:2:5: error: initializer element is not constant
b = input();
^
src.c:3:5: error: initializer element is not constant
c = input();
^
src.c:4:5: error: expected expression before 'int'
d = int(a) int(b) int(c);
^