#include <bits/stdc++.h>
using namespace std;
const int mod = 1000000007;
inline long long quick_pow(long long x, long long y) {
  long long re = 1;
  for (; y; y >>= 1) {
    if (y & 1) re = re * x % mod;
    x = x * x % mod;
  }
  return re;
}
int n, m;
long long ans;
int main() {
  cin >> n >> m;
  ans = quick_pow(m, n);
  int i;
  for (i = 0; i < n; ++i)
    ans = (ans + quick_pow(m, n - i) * quick_pow(2 * m - 1, i) % mod) % mod;
  cout << ans;
  return 0;
}

### Prompt

Create a solution in Cpp for 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 = 1000000007;
inline long long quick_pow(long long x, long long y) {
  long long re = 1;
  for (; y; y >>= 1) {
    if (y & 1) re = re * x % mod;
    x = x * x % mod;
  }
  return re;
}
int n, m;
long long ans;
int main() {
  cin >> n >> m;
  ans = quick_pow(m, n);
  int i;
  for (i = 0; i < n; ++i)
    ans = (ans + quick_pow(m, n - i) * quick_pow(2 * m - 1, i) % mod) % mod;
  cout << ans;
  return 0;
}

```