uva 10523

import java.io.*;import java.util.*;import java.math.*;public class Main{public static void main(String[] args) {Scanner cin = new Scanner(new BufferedInputStream(System.in));while(cin.hasNext()){     int n = cin.nextInt();     BigInteger a = cin.nextBigInteger();     BigInteger sum = BigInteger.ZERO;     for(int i = 1; i <= n; ++i){     BigInteger t = BigInteger.valueOf(i);     sum = sum.add(t.multiply(a.pow(i)));     }     System.out.println(sum);}}}