#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
#include <sstream>
#include <iostream>
#include <string>
#include <cstdio>
#include <cmath>

using namespace std;

int main() {

	long long A, B, C, D;
	cin >> A >> B >> C >> D;
	cout << A*B*C%D << endl;

	return 0;
}