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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<climits>
#include<cstdlib>
#include<string>
#include<vector>
#include<map>
#include<queue>
#include<set>
#include<algorithm>

#define ll long long
#define dl double
#define mod 1000000007
#define sz 1005
#define szz 150

using namespace std;

int main()
{
    ll n,k;

    scanf("%lld %lld",&n,&k);

    ll a=1,m=2;

    for(ll i=1;i<=n;i++)
    {
        ll v1=a*m;
        ll v2=a+k;

        a=min(v1, v2);
    }

    printf("%lld\n",a);

    return (0);
}