#include <bits/stdc++.h>
using namespace std;
inline int read() {
  register int data = 0, w = 1;
  char ch = 0;
  while (ch != '-' && (ch < '0' || ch > '9')) ch = getchar();
  if (ch == '-') w = -1, ch = getchar();
  while (ch >= '0' && ch <= '9')
    data = (data << 1) + (data << 3) + (ch ^ 48), ch = getchar();
  return data * w;
}
int n, m;
const int mod = 1e9 + 7;
int KSM(int x, int k) {
  int tmp = 1, y = x;
  for (int i = k; i; i >>= 1, y = 1ll * y * y % mod)
    if (i & 1) tmp = 1ll * tmp * y % mod;
  return tmp;
}
int main() {
  n = read(), m = read();
  if (m == 1) return cout << n + 1 << '\n', 0;
  int ans = 1, x = KSM(m - 1, mod - 2),
      y = (KSM(m - 1, mod - 2) + KSM(m, mod - 2)) % mod, t = 1, s = 1;
  for (int i = 1; i <= n; i++)
    s = 1ll * s * (m - 1) % mod, ans = (ans + 1ll * x * t % mod * s) % mod,
    t = 1ll * t * y % mod;
  ans = 1ll * ans * KSM(m, n) % mod;
  cout << ans << '\n';
  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;
inline int read() {
  register int data = 0, w = 1;
  char ch = 0;
  while (ch != '-' && (ch < '0' || ch > '9')) ch = getchar();
  if (ch == '-') w = -1, ch = getchar();
  while (ch >= '0' && ch <= '9')
    data = (data << 1) + (data << 3) + (ch ^ 48), ch = getchar();
  return data * w;
}
int n, m;
const int mod = 1e9 + 7;
int KSM(int x, int k) {
  int tmp = 1, y = x;
  for (int i = k; i; i >>= 1, y = 1ll * y * y % mod)
    if (i & 1) tmp = 1ll * tmp * y % mod;
  return tmp;
}
int main() {
  n = read(), m = read();
  if (m == 1) return cout << n + 1 << '\n', 0;
  int ans = 1, x = KSM(m - 1, mod - 2),
      y = (KSM(m - 1, mod - 2) + KSM(m, mod - 2)) % mod, t = 1, s = 1;
  for (int i = 1; i <= n; i++)
    s = 1ll * s * (m - 1) % mod, ans = (ans + 1ll * x * t % mod * s) % mod,
    t = 1ll * t * y % mod;
  ans = 1ll * ans * KSM(m, n) % mod;
  cout << ans << '\n';
  return 0;
}

```