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

public class Main {

	public static void main (String[] args) {

		Scanner sc = new Scanner(System.in);
		
		BigInteger a = BigInteger.valueOf(sc.nextInt());
		BigInteger b = BigInteger.valueOf(sc.nextInt());
		BigInteger c = BigInteger.valueOf(sc.nextInt());
		BigInteger d = BigInteger.valueOf(sc.nextInt());
		
		System.out.println(a.multiply(b).multiply(c).remainder(d));

		sc.close();

	}

}