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

public class Main {
    private static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) throws Exception {
        BigInteger a = new BigInteger(sc.next());
        BigInteger b = new BigInteger(sc.next());
        BigInteger c = new BigInteger(sc.next());
        BigInteger d = new BigInteger(sc.next());
        BigInteger ret = mod(mod(mod(a,d).multiply(b),d).multiply(c),d);
        System.out.println(ret);
    }
    
    public static BigInteger mod(BigInteger a,BigInteger b) {
        return a.mod(b);
    }
}