Count the number of n x m matrices A satisfying the following condition modulo (109+7). * Ai, j ∈ {0, 1, 2} for all 1 ≤ i ≤ n, 1 ≤ j ≤ m. * Ai, j ≤ Ai + 1, j for all 1 ≤ i * Ai, j ≤ Ai, j + 1 for all 1 ≤ i ≤ n, 1 ≤ j

输入描述:

The input consists of several test cases and is terminated by end-of-file.Each test case contains two integers n and m.

输出描述:

For each test case, print an integer which denotes the result.

备注:

* 1 ≤ n, m ≤ 103* The number of test cases does not exceed 105.