#define _USE_MATH_DEFINES
 
#include <iostream>
#include <iomanip>
#include <sstream>
 
#include <algorithm>
#include <cmath>
 
#include <string>
#include <queue>
#include <vector>
#include <complex>
#include <set>
#include <map>
#include <stack>
#include <list>

#include <valarray>

#include<cassert>//assert();
//#include <random>//xAOJ
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
 
#define PII pair<int,int>
/////////
typedef long long LL;
typedef long double LD;
typedef unsigned long long ULL;
/////////
using namespace::std;
/////////
/////////

void solve(){
	//10^27
	ULL A,B,C,D;
	cin >> A >> B >> C >> D;
	A %= D;
	B %= D;
	C %= D;
	ULL ans;
	ans = (A*B)%D;
	ans = (ans*C)%D;
	cout << ans << endl;
}

int main(void){
    std::cin.tie(0); 
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    //cout << setprecision(16);//
	
	solve();
	
	return 0;
}