#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const long long N = 1e6 + 30;
long long n, m, k;
long long dp[N], s[N];
signed main() {
  cin >> n >> m;
  dp[0] = 1;
  for (long long i = 1; i <= n; i++) {
    dp[i] = m * (dp[i - 1] * 2 - s[i - 1]) % mod;
    s[i] = (s[i - 1] * (m - 1) + dp[i - 1]) % mod;
  }
  cout << (dp[n] + mod) % mod << endl;
  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 long long mod = 1e9 + 7;
const long long N = 1e6 + 30;
long long n, m, k;
long long dp[N], s[N];
signed main() {
  cin >> n >> m;
  dp[0] = 1;
  for (long long i = 1; i <= n; i++) {
    dp[i] = m * (dp[i - 1] * 2 - s[i - 1]) % mod;
    s[i] = (s[i - 1] * (m - 1) + dp[i - 1]) % mod;
  }
  cout << (dp[n] + mod) % mod << endl;
  return 0;
}

```