public class Program
{
    public static void Main()
    {
        //int num = int.Parse(Console.ReadLine() ?? string.Empty);
        string[] str = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        //string str = Console.ReadLine() ?? string.Empty;


        int a = int.Parse(str[0]);
        int b = int.Parse(str[1]);
        int c = int.Parse(str[2]);
        int d = int.Parse(str[3]);
        long ab = ((long)a * (long)b);
        long abc = ab * (long)c;
        long ans = abc % (long)d;

        Console.WriteLine(ans);


    }
}