import java.util.Scanner;
import java.math.BigInteger;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        BigInteger a = new BigInteger(sc.next());
        BigInteger b = new BigInteger(sc.next());
        BigInteger c = new BigInteger(sc.next());
        BigInteger d = new BigInteger(sc.next());

        BigInteger bi = new BigInteger("0");

        bi = bi.add(a);
        bi = bi.multiply(b);
        bi = bi.multiply(c);
        bi = bi.remainder(d);
        
        System.out.println(bi.toString());
    }
}