#define _USE_MATH_DEFINES

#include <iostream>		//cin, cout
#include <vector>		//vector
#include <algorithm>	//sort,min,max,count
#include <string>		//string,getline, to_string
#include <cstdlib>		//abs(int)
#include <utility>		//swap, pair
#include <deque>		//deque
#include <climits>		//INT_MAX
#include <bitset>		//bitset
#include <cmath>		//sqrt, ceil. M_PI, pow, sin
#include <ios>			//fixed
#include <iomanip>		//setprecision
#include <sstream>		//stringstream
#include <numeric>		//gcd, assumlate
#include <random>		//randam_device
#include <limits>		//numeric_limits

using namespace std;
constexpr long long int D_MOD = 1000000007;

int main() {

	long long int a, b, c, d;
	cin >> a >> b >> c >> d;

	long long int A = a % d;
	long long int B = b % d;
	long long int C = c % d;

	long long int AB = ((A % d) * (B % d)) % d;
	long long int ans = ((AB % d) * (C % d)) % d;

	cout << ans << endl;

	return 0;

}