import java.util.Scanner;

public class Main {
	public static void main(String[] args){

		Scanner sc = new Scanner(System.in);
		int num1 = sc.nextInt();
		int num2 = sc.nextInt();
		int num3 = sc.nextInt();
		int product = num1*num2*num3;
		int num4 = sc.nextInt();
		System.out.println(product%num4);

	}
}