#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
inline int fpm(int a, int b) {
  int ret = 1;
  while (b) {
    if (b & 1) ret = 1ll * ret * a % MOD;
    a = 1ll * a * a % MOD, b >>= 1;
  }
  return ret;
}
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  int ans = fpm(m, n);
  for (int j = 1; j <= n; ++j)
    (ans += 1ll * fpm(m, n - j + 1) * fpm(2 * m - 1, j - 1) % MOD) %= MOD;
  cout << ans << endl;
  return 0;
}

### Prompt

Please create a solution in CPP 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 MOD = 1e9 + 7;
inline int fpm(int a, int b) {
  int ret = 1;
  while (b) {
    if (b & 1) ret = 1ll * ret * a % MOD;
    a = 1ll * a * a % MOD, b >>= 1;
  }
  return ret;
}
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  int ans = fpm(m, n);
  for (int j = 1; j <= n; ++j)
    (ans += 1ll * fpm(m, n - j + 1) * fpm(2 * m - 1, j - 1) % MOD) %= MOD;
  cout << ans << endl;
  return 0;
}

```