#include <bits/stdc++.h>
using namespace std;
long long base = 1000000007;
long long pow(long long x, long long i) {
  if (!i) return 1;
  long long tmp = pow(x, i / 2);
  tmp = tmp * tmp % base;
  return (i & 1) ? tmp * x % base : tmp;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  long long n, m;
  cin >> n >> m;
  if (m == 1)
    cout << n + 1;
  else
    cout << ((m * pow(2 * m - 1, n) % base - pow(m, n) + base) % base) *
                pow(m - 1, base - 2) % base;
}

### Prompt

Your challenge is to write 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;
long long base = 1000000007;
long long pow(long long x, long long i) {
  if (!i) return 1;
  long long tmp = pow(x, i / 2);
  tmp = tmp * tmp % base;
  return (i & 1) ? tmp * x % base : tmp;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  long long n, m;
  cin >> n >> m;
  if (m == 1)
    cout << n + 1;
  else
    cout << ((m * pow(2 * m - 1, n) % base - pow(m, n) + base) % base) *
                pow(m - 1, base - 2) % base;
}

```