import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		long A = scan.nextLong();
		long B = scan.nextLong();
		long C = scan.nextLong();
		long D = scan.nextLong();
		scan.close();
		long ans = (((A % D) * (B % D)) % D * (C % D)) % D;
		System.out.println(ans);
	}
}