#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 10, MOD = 1e9 + 7;
int n, m, pw[2][N];
int main() {
  scanf("%d%d", &n, &m);
  pw[0][0] = pw[1][0] = 1;
  for (int i = 1; i < N; i++) {
    pw[0][i] = 1ll * pw[0][i - 1] * m % MOD;
    pw[1][i] = 1ll * pw[1][i - 1] * (m + m - 1) % MOD;
  }
  int ret = pw[0][n];
  for (int i = 0; i < n; i++) {
    ret = (ret + 1ll * pw[0][i + 1] * pw[1][n - i - 1] % MOD) % MOD;
  }
  printf("%d\n", ret);
  return 0;
}

### Prompt

Your task is to create 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>
using namespace std;
const int N = 1e6 + 10, MOD = 1e9 + 7;
int n, m, pw[2][N];
int main() {
  scanf("%d%d", &n, &m);
  pw[0][0] = pw[1][0] = 1;
  for (int i = 1; i < N; i++) {
    pw[0][i] = 1ll * pw[0][i - 1] * m % MOD;
    pw[1][i] = 1ll * pw[1][i - 1] * (m + m - 1) % MOD;
  }
  int ret = pw[0][n];
  for (int i = 0; i < n; i++) {
    ret = (ret + 1ll * pw[0][i + 1] * pw[1][n - i - 1] % MOD) % MOD;
  }
  printf("%d\n", ret);
  return 0;
}

```