#include <bits/stdc++.h>
using namespace std;
const int MOD = 1000000007;
int add(int a, int b) {
  int c = a + b;
  return c >= MOD ? c - MOD : c;
}
int mul(int a, int b) {
  return a ? (b < MOD / a ? a * b : (long long)a * b % MOD) : 0;
}
template <typename T>
int powMod(int a, T b) {
  int res = 1;
  for (; b; b >>= 1, a = mul(a, a))
    if (b & 1) res = mul(res, a);
  return res;
}
int n, m, m21;
int main() {
  scanf("%d%d", &n, &m);
  m21 = (m << 1) - 1;
  int res = powMod(m, n);
  for (int i = (0); i < (n); i++) {
    res = add(res, mul(powMod(m, n - i), powMod(m21, i)));
  }
  printf("%d\n", res);
}

### 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;
const int MOD = 1000000007;
int add(int a, int b) {
  int c = a + b;
  return c >= MOD ? c - MOD : c;
}
int mul(int a, int b) {
  return a ? (b < MOD / a ? a * b : (long long)a * b % MOD) : 0;
}
template <typename T>
int powMod(int a, T b) {
  int res = 1;
  for (; b; b >>= 1, a = mul(a, a))
    if (b & 1) res = mul(res, a);
  return res;
}
int n, m, m21;
int main() {
  scanf("%d%d", &n, &m);
  m21 = (m << 1) - 1;
  int res = powMod(m, n);
  for (int i = (0); i < (n); i++) {
    res = add(res, mul(powMod(m, n - i), powMod(m21, i)));
  }
  printf("%d\n", res);
}

```