#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <iomanip>
#include <cmath>
#include <functional>
using namespace std;
#define diff(x,y) ((x > y) ? (x - y) : (y - x))
#define us(x) ((x > 0) ? x : x * -1)
#define change(x) (x ? false : true)
#define lli long long int


int main() {
	lli a, b, c, d;
	cin >> a >> b >> c >> d;
	cout << a * b * c % d << endl;
	return 0;
}