#include <bits/stdc++.h>
using namespace std;
const int mod = (int)1e9 + 7;
template <class X, class Y>
void minimize(X &x, const Y &y) {
  if (x > y) x = y;
}
template <class X, class Y>
void maximize(X &x, const Y &y) {
  if (x < y) x = y;
}
int n, m, s[1000100];
void process(void) {
  scanf("%d%d", &n, &m);
  s[0] = 1;
  int sub = 0;
  for (int i = (1), _b = (n); i <= _b; i = i + 1) {
    s[i] = (2LL * s[i - 1] * m % mod - sub + mod) % mod;
    sub = 1LL * sub * (m - 1) % mod;
    sub = (sub + 1LL * m * s[i - 1]) % mod;
  }
  printf("%d\n", s[n]);
}
int main(void) {
  process();
  return 0;
}

### Prompt

Generate 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 int mod = (int)1e9 + 7;
template <class X, class Y>
void minimize(X &x, const Y &y) {
  if (x > y) x = y;
}
template <class X, class Y>
void maximize(X &x, const Y &y) {
  if (x < y) x = y;
}
int n, m, s[1000100];
void process(void) {
  scanf("%d%d", &n, &m);
  s[0] = 1;
  int sub = 0;
  for (int i = (1), _b = (n); i <= _b; i = i + 1) {
    s[i] = (2LL * s[i - 1] * m % mod - sub + mod) % mod;
    sub = 1LL * sub * (m - 1) % mod;
    sub = (sub + 1LL * m * s[i - 1]) % mod;
  }
  printf("%d\n", s[n]);
}
int main(void) {
  process();
  return 0;
}

```