import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		long a = sc.nextInt();
		long b = sc.nextInt();
		long c = sc.nextInt();
		long d = sc.nextInt();
		long ans = (((a % d) * (b % d)) % d * (c % d)) % d;
	    System.out.println(ans);
	}
}