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: 124710.


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: 124816263646566676.

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