UVa 10523 - Very Easy !!!

// UVa 10523 - Very Easy !!!

import java.math.BigInteger;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		while (scanner.hasNextInt()) {
			int n = scanner.nextInt();
			BigInteger a = scanner.nextBigInteger();
			BigInteger sol = BigInteger.ZERO;
			BigInteger power = BigInteger.ONE;
			for (int i = 1; i <= n; i++) {
				power = power.multiply(a);
				sol = sol.add(power.multiply(BigInteger.valueOf(i)));

			}
			System.out.println(sol);
		}

	}

}