#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:134217728")
using namespace std;
const int N = 1e6 + 100;
long long M = 1e9 + 7;
long long binpow(long long deg, long long n) {
  if (deg == 0) return 1;
  if (deg & 1) return binpow(deg - 1, n) * n % M;
  long long b = binpow(deg / 2, n);
  return b * b % M;
}
long long n, m;
long long f(long long n) {
  if (n == 1) return m;
  return ((2 * m - 1) * f(n - 1) + binpow(n, m)) % M;
}
int main() {
  cin >> n >> m;
  cout << (f(n) + binpow(n, m)) % M;
  return 0;
}

### Prompt

In Cpp, your task is to solve 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>
#pragma comment(linker, "/STACK:134217728")
using namespace std;
const int N = 1e6 + 100;
long long M = 1e9 + 7;
long long binpow(long long deg, long long n) {
  if (deg == 0) return 1;
  if (deg & 1) return binpow(deg - 1, n) * n % M;
  long long b = binpow(deg / 2, n);
  return b * b % M;
}
long long n, m;
long long f(long long n) {
  if (n == 1) return m;
  return ((2 * m - 1) * f(n - 1) + binpow(n, m)) % M;
}
int main() {
  cin >> n >> m;
  cout << (f(n) + binpow(n, m)) % M;
  return 0;
}

```