#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr ll M = 1e9 + 7;
ll mpw(ll a, ll b) {
  return (b == 0LL ? 1LL
                   : (mpw(a * a % M, b / 2LL) * ((b & 1LL) ? a : 1LL) % M));
}
int main() {
  ll n, m;
  cin >> n >> m;
  if (m == 1)
    cout << n + 1 << endl;
  else
    cout << (mpw(m, n) + m * mpw(m - 1, M - 2) % M *
                             (mpw(2LL * m - 1LL, n) - mpw(m, n) + M)) %
                M
         << endl;
}

### 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>
using namespace std;
using ll = long long;
constexpr ll M = 1e9 + 7;
ll mpw(ll a, ll b) {
  return (b == 0LL ? 1LL
                   : (mpw(a * a % M, b / 2LL) * ((b & 1LL) ? a : 1LL) % M));
}
int main() {
  ll n, m;
  cin >> n >> m;
  if (m == 1)
    cout << n + 1 << endl;
  else
    cout << (mpw(m, n) + m * mpw(m - 1, M - 2) % M *
                             (mpw(2LL * m - 1LL, n) - mpw(m, n) + M)) %
                M
         << endl;
}

```