#include<iostream>
#include<stdio.h>

using namespace std;

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

	cin >> a >> b >> c >>d;

	ans = ((a%d)*(b%d)*(c%d)) % d;

	//cout << ans << endl;
	printf("%d\n", ans);

	return 0;
	
}