#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
void fix(long long& a) {
  a %= mod;
  if (a < 0) {
    a += mod;
  }
}
signed main() {
  long long n, m, x = 1, y = 0;
  cin >> n >> m;
  for (long long i = 0; i < n; ++i) {
    y = 2 * m * y - y + x;
    x *= m;
    fix(y);
    fix(x);
  }
  x = x + m * y;
  fix(x);
  cout << x;
  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 long long mod = 1e9 + 7;
void fix(long long& a) {
  a %= mod;
  if (a < 0) {
    a += mod;
  }
}
signed main() {
  long long n, m, x = 1, y = 0;
  cin >> n >> m;
  for (long long i = 0; i < n; ++i) {
    y = 2 * m * y - y + x;
    x *= m;
    fix(y);
    fix(x);
  }
  x = x + m * y;
  fix(x);
  cout << x;
  return 0;
}

```