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: Runtime Error)

#include <stdio.h>

int main(void) {
  int n, k, ktmp, count = 0, ans = 1, i;
  scanf("%d\n%d", &n, &k);
  ktmp = k;
  if (n == 1) {
    printf("2\n");
    return 1;
  }
  // kが2の何乗ぐらいか調べる
  while (ktmp != 0) {
    ktmp = ktmp / 2;
    count++;
  }
  //その回数だけ2倍する
  for (i = 0; i < count; i++) ans = ans * 2;
  //残りの回数kを足す
  ans = ans + (n - count) * k;
  printf("%d\n", ans);
  return 0;
}