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.