Domino Tiling

Problem Description

Given an $n \times m$ chessboard, you need to cover it entirely with $1 \times 2$ dominoes. Count the number of distinct tilings. Since the answer may be very large, output it modulo $10^9 + 7$.

Input Format

The first line contains two integers $n, m$.

Output Format

Output one line containing a single integer: the answer modulo $10^9 + 7$.

Sample Input

2 3

Sample Output

3

Constraints

For $100\%$ of the test cases, $1 \le n \le 10^9$, $1 \le m \le 5$.