import java.util.*;


public class Main_yukicoder373 {

    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 ret = (a % d) * (b % d) % d;
        ret = ret * (c % d) % d;

        System.out.println(ret);

        sc.close();
    }
}