#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
long long pow_mod(long long a, long long b, long long p) {
  long long tmp = 1;
  for (long long i = b; i; i >>= 1, a = a * a % p)
    if (i & a) tmp = (tmp * a) % p;
  return tmp;
}
long long n, m, r;
long long ans;
int main() {
  cin >> n >> m;
  ans = 2 * m;
  r = 1;
  for (int i = 2; i <= n; i++) {
    r = r * m % mod;
    ans = (ans * (2 * m - 1) + r) % 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 long long mod = 1e9 + 7;
long long pow_mod(long long a, long long b, long long p) {
  long long tmp = 1;
  for (long long i = b; i; i >>= 1, a = a * a % p)
    if (i & a) tmp = (tmp * a) % p;
  return tmp;
}
long long n, m, r;
long long ans;
int main() {
  cin >> n >> m;
  ans = 2 * m;
  r = 1;
  for (int i = 2; i <= n; i++) {
    r = r * m % mod;
    ans = (ans * (2 * m - 1) + r) % mod;
  }
  cout << ans << endl;
  return 0;
}

```