#include <bits/stdc++.h>
#define PI 3.14159265359
using namespace std;
const int64_t mod = 1e9 + 7;

int main() {
	int64_t A, B, C, D;
	cin >> A >> B >> C >> D;

	int n = (A % D) * (B % D) * (C % D);
	n %= D;

	cout << n << endl;
}