#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
inline int add(int a, int b) {
  a += b;
  if (a >= mod) a -= mod;
  return a;
}
inline int mul(int a, int b) {
  long long ret = 1LL * a * b;
  if (ret >= mod) ret %= mod;
  return ret;
}
inline int pwm(int a, long long p) {
  int m = a, ret = 1;
  while (p) {
    if (p & 1) ret = mul(ret, m);
    m = mul(m, m);
    p >>= 1;
  }
  return ret;
}
int n, m;
int main() {
  scanf("%d", &n), scanf("%d", &m);
  int res = 2 * m;
  for (int i = 2; i <= n; i++) {
    res = add(mul(res, (2 * m - 1)), pwm(m, i - 1));
  }
  cout << res;
}

### Prompt

Your challenge is to write 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 = 1e9 + 7;
inline int add(int a, int b) {
  a += b;
  if (a >= mod) a -= mod;
  return a;
}
inline int mul(int a, int b) {
  long long ret = 1LL * a * b;
  if (ret >= mod) ret %= mod;
  return ret;
}
inline int pwm(int a, long long p) {
  int m = a, ret = 1;
  while (p) {
    if (p & 1) ret = mul(ret, m);
    m = mul(m, m);
    p >>= 1;
  }
  return ret;
}
int n, m;
int main() {
  scanf("%d", &n), scanf("%d", &m);
  int res = 2 * m;
  for (int i = 2; i <= n; i++) {
    res = add(mul(res, (2 * m - 1)), pwm(m, i - 1));
  }
  cout << res;
}

```