using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

class Magatro
{
    static void Main()
    {
        long[] ABCD = Console.ReadLine().Split(' ').Select(s => long.Parse(s)).ToArray();
        long A, B, C, D;
        A = ABCD[0];
        B = ABCD[1];
        C = ABCD[2];
        D = ABCD[3];
        A %= D;
        B %= D;
        C %= D;
        A = (A * B) % D;
        A = (A * C) % D;
        Console.WriteLine(A);
    }
   

}