using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static string InputPattern = "InputX";

    static List<string> GetInputList()
    {
        var WillReturn = new List<string>();

        if (InputPattern == "Input1") {
            WillReturn.Add("1 2 3 4");
            //2
            //「1かける2かける3わる4の余り」は2です
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("2 2 2 2");
            //0
            //「2かける2かける2わる2の余り」は0です
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static void Main()
    {
        List<string> InputList = GetInputList();
        long[] wkArr = InputList[0].Split(' ').Select(X => long.Parse(X)).ToArray();

        long A = wkArr[0];
        long B = wkArr[1];
        long C = wkArr[2];
        long D = wkArr[3];

        long Answer = (A * B) % D;
        Answer = (Answer * C) % D;
        Console.WriteLine(Answer);
    }
}