package yukicoder;
import java.util.Scanner;
public class Main{
	public static void main(String[] args){
		new Main().solve();
	}
	void solve(){
		Scanner sc=new Scanner(System.in);
		long a,b,c,d;
		a=sc.nextLong();b=sc.nextLong();c=sc.nextLong();d=sc.nextLong();
		long ans=1;
		ans=a%d;
		ans=ans*b%d;
		ans=ans*c%d;
		System.out.println(ans);
	}
}