Addition and Multiplication

Source: AtCoder

Version: Phuoc Hung OJ Extended

Problem Statement

A board initially displays $1$. Perform exactly $N$ operations. Each operation either doubles the current value or adds $K$. Find the minimum possible value after exactly $N$ operations.

Input

The first line contains $N$. The second line contains $K$.

Output

Print the minimum possible value.

Subtasks

General constraints:

• $1 \le N,K \le 10$.

• Subtask 1 (20 points): $N \le 4$, $K \le 4$

• Subtask 2 (30 points): $N \le 7$, $K \le 7$

• Subtask 3 (50 points): No additional constraints.

Examples

Input

4
3

Output

10

Explanation

Starting from $1$, choose the smaller next value at every step: $1\to2\to4\to7\to10$.