#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
int ksm(int x, int y = mod - 2) {
  int z = 1;
  for (; y; y >>= 1, x = 1ll * x * x % mod)
    if (y & 1) z = 1ll * z * x % mod;
  return z;
}
int n, m, res;
int main() {
  scanf("%d%d", &n, &m), res = ksm(m, n);
  for (int i = 0, j = res, invm = ksm(m), k = 1; i < n;
       i++, j = 1ll * j * invm % mod, k = 1ll * k * (2 * m - 1) % mod)
    (res += 1ll * j * k % mod) %= mod;
  printf("%d\n", res);
  return 0;
}

### Prompt

Construct a cpp code solution to the problem outlined:

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 = 1e9 + 7;
int ksm(int x, int y = mod - 2) {
  int z = 1;
  for (; y; y >>= 1, x = 1ll * x * x % mod)
    if (y & 1) z = 1ll * z * x % mod;
  return z;
}
int n, m, res;
int main() {
  scanf("%d%d", &n, &m), res = ksm(m, n);
  for (int i = 0, j = res, invm = ksm(m), k = 1; i < n;
       i++, j = 1ll * j * invm % mod, k = 1ll * k * (2 * m - 1) % mod)
    (res += 1ll * j * k % mod) %= mod;
  printf("%d\n", res);
  return 0;
}

```