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

public class yukicoder
{
    public static void Main()
    {
        long[] n = Console.ReadLine().Split(' ').Select(x => long.Parse(x)).ToArray();

        Console.WriteLine(n[0] * n[1] % n[3] * n[2] % n[3]);

    }
}