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;

namespace AtCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            //[summary]B - Addition and Multiplication
            var line = ReadLines(2);
            int N = line[0];
            int K = line[1];
            int num = 1;

            for(int i = 0; i < N; i++)
            {
                if (num < K)
                {
                    num *= 2;
                }
                else
                {
                    num += K;
                }
            }

            Console.WriteLine(num);
        }

        static List<int> ReadLines(int count = 0)
        {
            //[summary]コンソールの値を読み込む
            var lines = new List<int>();
            string s;

            //読み込む行数が未指定のときは、1行目の値を"count"とみなす
            if (count == 0)
            {
                s = Console.ReadLine().TrimEnd();
                count = int.Parse(s);
            }

            for (int i = 0; i < count; i++)
            {
                s = Console.ReadLine().TrimEnd();
                lines.Add(int.Parse(s));
            }

            return lines;
        }
    }
}