#include <bits/stdc++.h>
using namespace std;
long long qow(long long x, long long y) {
  return y ? (y & 1 ? x * qow(x, y - 1) % 1000000007
                    : qow(x * x % 1000000007, y / 2))
           : 1;
}
long long n, m, s, ans;
int main() {
  scanf("%I64d%I64d", &n, &m);
  ans = qow(m, n);
  s = qow(m - 1, n - 1) * m % 1000000007;
  for (long long k = 1; k < n; k++)
    ans += s, s *= m * (n - k + 1) % 1000000007, s %= 1000000007,
        s *= qow((m - 1) * k % 1000000007, 1000000007 - 2), s %= 1000000007;
  printf("%I64d\n", m == 1 ? n + 1 : (ans + s) % 1000000007);
  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 qow(long long x, long long y) {
  return y ? (y & 1 ? x * qow(x, y - 1) % 1000000007
                    : qow(x * x % 1000000007, y / 2))
           : 1;
}
long long n, m, s, ans;
int main() {
  scanf("%I64d%I64d", &n, &m);
  ans = qow(m, n);
  s = qow(m - 1, n - 1) * m % 1000000007;
  for (long long k = 1; k < n; k++)
    ans += s, s *= m * (n - k + 1) % 1000000007, s %= 1000000007,
        s *= qow((m - 1) * k % 1000000007, 1000000007 - 2), s %= 1000000007;
  printf("%I64d\n", m == 1 ? n + 1 : (ans + s) % 1000000007);
  return 0;
}

```