easy:

a, b = map(float, input().split())
c, d = map(float, input().split())
real = a * c - b * d
imag = a * d + b * c
print(f"{real:g} {imag:g}")

C++ :

#include <stdio.h>

int main() {
	int a, b;
	int c, d;

	scanf("%d %d", &a, &b);

	scanf("%d %d", &c, &d);

	printf("%d %d\n", (a*c-b*d), (a*d+b*c));
	return 0;
}