#include <bits/stdc++.h>
using namespace std;
int n, m;
long long a, b;
int main() {
  scanf("%d %d", &n, &m);
  a = 0, b = 1;
  for (int i = (1); i <= (n); i++) {
    long long c, d;
    d = 2 * m * b - a;
    a = m * b + (m - 1) * a;
    b = d;
    a %= 1000000007;
    b %= 1000000007;
  }
  printf("%lld\n", (b + 1000000007) % 1000000007);
  return 0;
}

### Prompt

In cpp, your task is to solve 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;
int n, m;
long long a, b;
int main() {
  scanf("%d %d", &n, &m);
  a = 0, b = 1;
  for (int i = (1); i <= (n); i++) {
    long long c, d;
    d = 2 * m * b - a;
    a = m * b + (m - 1) * a;
    b = d;
    a %= 1000000007;
    b %= 1000000007;
  }
  printf("%lld\n", (b + 1000000007) % 1000000007);
  return 0;
}

```