Different Subsets For All Tuples

2000ms

262144K

Description:

For a sequence a of n integers between 1 and m, inclusive, denote f(a) as the number of distinct subsequences of a (including the empty subsequence).

You are given two positive integers n and m. Let S be the set of all sequences of length n consisting of numbers from 1 to m. Compute the sum f(a) over all a in S modulo 10⁹ + 7.

Input:

The only line contains two integers n and m (1 ≤ n, m ≤ 10⁶) — the number of elements in arrays and the upper bound for elements.

Output:

Print the only integer c — the desired sum modulo 10⁹ + 7.

Sample Input:

1 3

Sample Output:

Sample Input:

2 2

Sample Output:

Sample Input:

3 3

Sample Output:

Informação

Provedor Codeforces

Código CF660E