import java.util.Scanner;

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