#include <bits/stdc++.h>
using namespace std;
long long read() {
  long long a = 0, b = getchar(), c = 1;
  while (!isdigit(b)) c = b == '-' ? -1 : 1, b = getchar();
  while (isdigit(b)) a = a * 10 + b - '0', b = getchar();
  return a * c;
}
long long n, m, p = 1, ans = 1, mod = 1e9 + 7;
int main() {
  n = read(), m = read();
  for (int i = 0; i < n; i++)
    ans = (2 * m * ans - (ans - p + mod) + mod) % mod, p = p * m % mod;
  printf("%lld", ans);
  return 0;
}

### Prompt

Please formulate 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 read() {
  long long a = 0, b = getchar(), c = 1;
  while (!isdigit(b)) c = b == '-' ? -1 : 1, b = getchar();
  while (isdigit(b)) a = a * 10 + b - '0', b = getchar();
  return a * c;
}
long long n, m, p = 1, ans = 1, mod = 1e9 + 7;
int main() {
  n = read(), m = read();
  for (int i = 0; i < n; i++)
    ans = (2 * m * ans - (ans - p + mod) + mod) % mod, p = p * m % mod;
  printf("%lld", ans);
  return 0;
}

```