#include <bits/stdc++.h>
using namespace std;
int n, m, f[1000005], g[1000005];
const int MOD = 1000000007;
int main() {
  cin >> n >> m;
  f[0] = 1;
  for (int i = 1; i <= n; i++) {
    f[i] = 1ll * m * (2 * f[i - 1] % MOD - g[i - 1] + MOD) % MOD;
    g[i] = (1ll * (m - 1) * g[i - 1] % MOD + f[i - 1]) % MOD;
  }
  cout << f[n] << endl;
  return 0;
}

### Prompt

Generate 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;
int n, m, f[1000005], g[1000005];
const int MOD = 1000000007;
int main() {
  cin >> n >> m;
  f[0] = 1;
  for (int i = 1; i <= n; i++) {
    f[i] = 1ll * m * (2 * f[i - 1] % MOD - g[i - 1] + MOD) % MOD;
    g[i] = (1ll * (m - 1) * g[i - 1] % MOD + f[i - 1]) % MOD;
  }
  cout << f[n] << endl;
  return 0;
}

```