using System;

class Program {
    static void Main(string[] args) {
        //入力
        string s = Console.ReadLine();

        string[] t = s.Split(' ');
        int A = int.Parse(t[0]);
        int B = int.Parse(t[1]);
        int C = int.Parse(t[2]);
        int D = int.Parse(t[3]);

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