import java.io.*;
import java.math.*;
import java.util.*;


public class Main {
	static int[] vy = {1,0,-1,0};
	static int[] vx = {0,1,0,-1};
	public static void main(String[] args) {	
		Scanner sc = new Scanner(System.in);
		PrintWriter out = new PrintWriter(System.out);
		System.out.println(sc.nextLong() * sc.nextLong() * sc.nextLong() % sc.nextLong());
	}
}