#include <bits/stdc++.h>
using namespace std;
const int64_t MOD = 1e9 + 7;
void add(int64_t& a, int64_t b) { a = (a + b) % MOD; }
void mul(int64_t& a, int64_t b) { a = a * b % MOD; }
int main() {
  int N, M;
  cin >> N >> M;
  static int64_t dp[int(1e6 + 1)][2];
  dp[0][0] = dp[0][1] = 1;
  for (int i = 0; i < N; i++) {
    add(dp[i + 1][0], (M - 1) * dp[i][0]);
    add(dp[i + 1][0], M * dp[i][0]);
    add(dp[i + 1][1], M * dp[i][0]);
    add(dp[i + 1][1], M * dp[i][1]);
  }
  cout << dp[N][1] << endl;
  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;
const int64_t MOD = 1e9 + 7;
void add(int64_t& a, int64_t b) { a = (a + b) % MOD; }
void mul(int64_t& a, int64_t b) { a = a * b % MOD; }
int main() {
  int N, M;
  cin >> N >> M;
  static int64_t dp[int(1e6 + 1)][2];
  dp[0][0] = dp[0][1] = 1;
  for (int i = 0; i < N; i++) {
    add(dp[i + 1][0], (M - 1) * dp[i][0]);
    add(dp[i + 1][0], M * dp[i][0]);
    add(dp[i + 1][1], M * dp[i][0]);
    add(dp[i + 1][1], M * dp[i][1]);
  }
  cout << dp[N][1] << endl;
  return 0;
}

```