#include <iostream>
#include <vector>
#include <cmath>
#include <iomanip>
#include <array>
#include <tuple>
#include <algorithm>
#include <map>
#include <stack>
#include <queue>
#include <set>
#include <list>

using namespace std;
using ull = unsigned long long;
using ll = long long;
using lli = long long int;
using ld = long double;
using pa = pair<int,int>;
#define SORT(v, n) sort(v, v+n);
#define VSORT(v) sort(v.begin(), v.end());
#define GRESORT(v) sort(v.begin(),v.end(),greater<int>())
#define REVERSE(v) reverse(v.begin(),v.end())
#define overlap(v) v.erase(unique(v.begin(),v.end()),v.end())
#define debug(x) cout << #x << ": " << x << endl
#define INF 999999999

//4近傍
//int dy[]={0, 0, 1, -1};
//int dx[]={1, -1, 0, 0};

//8近傍
//int dy[]={0,0,1,-1,1,1,-1,-1};
//int dx[]={1,-1,0,0,1,-1,1,-1};

lli mod = 1e9+7;

void solve(){
    lli a,b,c,d;
    cin >> a >> b >> c >> d;
    cout << a % d * b % d * c % d << endl;

}

int main(){
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);

    solve();

    return 0;
}