import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
    	Scanner sc = new Scanner(System.in);
    	
    	int A = sc.nextInt(), B = sc.nextInt(),
    		C = sc.nextInt(), D = sc.nextInt();
    	
    	System.out.println(A * B * C % D);
    }
}