#include <bits/stdc++.h>
int N, M, P = 1e9 + 7, F[1000005], Ans;
int main() {
  scanf("%d%d", &N, &M), *F = 1;
  for (int i = 1; i <= N; ++i) F[i] = (long long)F[i - 1] * M % P;
  for (int i = !--(M <<= 1), X = 1; i < N; ++i, X = (long long)X * M % P)
    Ans = (Ans + (long long)X * F[N - i]) % P;
  return printf("%d", (Ans + F[N]) % P), 0;
}

### Prompt

Please formulate a CPP solution to the following problem:

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.

Examples

Input

1 3


Output

6


Input

2 2


Output

14


Input

3 3


Output

174

### Response

```cpp
#include <bits/stdc++.h>
int N, M, P = 1e9 + 7, F[1000005], Ans;
int main() {
  scanf("%d%d", &N, &M), *F = 1;
  for (int i = 1; i <= N; ++i) F[i] = (long long)F[i - 1] * M % P;
  for (int i = !--(M <<= 1), X = 1; i < N; ++i, X = (long long)X * M % P)
    Ans = (Ans + (long long)X * F[N - i]) % P;
  return printf("%d", (Ans + F[N]) % P), 0;
}

```