import java.math.BigInteger;

/**
 * Created by nullzine on 2017/01/19.
 */
public class Main {

    public static void main(String[] args) {
        String[] strs = new java.util.Scanner(System.in).nextLine().split(" ");
        System.out.println(new BigInteger(strs[0]).multiply(new BigInteger(strs[1])).multiply(new BigInteger(strs[2])).mod(new BigInteger(strs[3])).toString());
    }

}