#include <bits/stdc++.h>
using namespace std;
const long long INF = 1 << 28;
const long long LINF = 1ll << 61;
const long long mod = 1e9 + 7;
long long n, m;
long long kissme(long long x, long long y) {
  long long ret = 1;
  while (y > 0) {
    if (y & 1) ret = ret * x % mod;
    x = x * x % mod;
    y >>= 1;
  }
  return ret;
}
int main() {
  cin >> n >> m;
  if (m == 1)
    cout << n + 1 << endl;
  else
    cout << (kissme(m, n) + m * kissme(m - 1, mod - 2) % mod *
                                (kissme(2 * m - 1, n) - kissme(m, n) + mod)) %
                mod;
  return 0;
}

### Prompt

Construct a CPP code solution to the problem outlined:

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 INF = 1 << 28;
const long long LINF = 1ll << 61;
const long long mod = 1e9 + 7;
long long n, m;
long long kissme(long long x, long long y) {
  long long ret = 1;
  while (y > 0) {
    if (y & 1) ret = ret * x % mod;
    x = x * x % mod;
    y >>= 1;
  }
  return ret;
}
int main() {
  cin >> n >> m;
  if (m == 1)
    cout << n + 1 << endl;
  else
    cout << (kissme(m, n) + m * kissme(m - 1, mod - 2) % mod *
                                (kissme(2 * m - 1, n) - kissme(m, n) + mod)) %
                mod;
  return 0;
}

```