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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main(void){
    int n,k;
    scanf("%d",&n);
    scanf("%d",&k);
    int hoge = 1;
    int i;
    int num = 1;
    switch (k) {
        case 1:
            num = 1;
            break;
        case 2:
            num = 1;
            break;
        case 3:
            num = 2;
            break;
        case 4:
            num = 2;
            break;
        case 5:
            num = 3;
            break;
        case 6:
            num = 3;
            break;
        case 7:
            num = 3;
            break;
        case 8:
            num = 3;
            break;
        case 9:
            num = 4;
            break;
        default:
            num = 4;
            break;
    }
    for(i=1;i<=num;i++){
        hoge *= 2;
    }
    if(n != num){
        for(i=1;i<=n-num;i++){
            hoge += k;
        }
    }
    printf("%d",hoge);
    printf("\n");
    return 0;
}