#include <iostream>
#include <vector>
using namespace std;

int main() {
	long long int a,b,c,d;
	scanf("%lld %lld %lld %lld", &a, &b, &c, &d);
	printf("%lld\n", (a%d)*(b%d)%d*(c%d)%d);
	return 0;
}