#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
const int N = 1e6 + 6;
int power(long long a, int p) {
  long long ans = 1;
  for (; p; p >>= 1) {
    if (p & 1) ans = ans * a % MOD;
    a = a * a % MOD;
  }
  return ans;
}
long long dp[N];
int n, m;
int main() {
  cin >> n >> m;
  dp[0] = 1;
  long long sum = 1;
  for (int i = 1; i <= n; ++i) {
    dp[i] = sum * m % MOD;
    sum = sum * (m - 1) % MOD;
    sum = (sum + dp[i] % MOD);
  }
  long long ans = power(m, n);
  for (int i = 1; i <= n; ++i) {
    ans = (ans + dp[i] * power(m, n - i)) % MOD;
  }
  cout << ans << 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 int MOD = 1e9 + 7;
const int N = 1e6 + 6;
int power(long long a, int p) {
  long long ans = 1;
  for (; p; p >>= 1) {
    if (p & 1) ans = ans * a % MOD;
    a = a * a % MOD;
  }
  return ans;
}
long long dp[N];
int n, m;
int main() {
  cin >> n >> m;
  dp[0] = 1;
  long long sum = 1;
  for (int i = 1; i <= n; ++i) {
    dp[i] = sum * m % MOD;
    sum = sum * (m - 1) % MOD;
    sum = (sum + dp[i] % MOD);
  }
  long long ans = power(m, n);
  for (int i = 1; i <= n; ++i) {
    ans = (ans + dp[i] * power(m, n - i)) % MOD;
  }
  cout << ans << endl;
  return 0;
}

```