Problem:
Score : 200 points

Problem Statement

Square1001 has seen an electric bulletin board displaying the integer 1.
He can perform the following operations A and B to change this value:

Operation A: The displayed value is doubled.

Operation B: The displayed value increases by K.

Square1001 needs to perform these operations N times in total.
Find the minimum possible value displayed in the board after N operations.

Constraints

1 \leq N, K \leq 10

All input values are integers.

Input

Input is given from Standard Input in the following format:

N
K

Output

Print the minimum possible value displayed in the board after N operations.

Sample Input 1

4
3

Sample Output 1

10

The value will be minimized when the operations are performed in the following order: A, A, B, B.

In this case, the value will change as follows: 1 → 2 → 4 → 7 → 10.

Sample Input 2

10
10

Sample Output 2

76

The value will be minimized when the operations are performed in the following order: A, A, A, A, B, B, B, B, B, B.

In this case, the value will change as follows: 1 → 2 → 4 → 8 → 16 → 26 → 36 → 46 → 56 → 66 → 76.

By the way, this contest is AtCoder Beginner Contest 076.

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace B_AdditionandMultiplication
{
    class Program
    {
        static void Main(string[] args)
        {
            int intN = int.Parse(Console.ReadLine()); // 操作回数入力値

            int intK = int.Parse(Console.ReadLine()); // 電光掲示板整数入力値

            int intAns = 1; // 電光掲示板整数1
            int i = 1;      // 操作回数


            // Aの操作
            while (i <= intN) {
                intAns *= 2;
                i++;
                if (intAns > intK) {
                    break;  
                }
            }


            // Bの操作
            while (i <= intN)
            {
                intAns += intK;
                i++;
            }

            Console.WriteLine(intAns);


        }
    }
}