#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007LL;
const long long inf = 1e18;
inline long long max(long long a, int32_t b) { return a > b ? a : b; }
inline long long max(int32_t a, long long b) { return a > b ? a : b; }
inline long long min(long long a, int32_t b) { return a < b ? a : b; }
inline long long min(int32_t a, long long b) { return a < b ? a : b; }
long long d4_1[4] = {1, 0, -1, 0};
long long d4_2[4] = {0, 1, 0, -1};
long long d8_1[8] = {1, 1, 1, -1, -1, -1, 0, 0};
long long d8_2[8] = {0, -1, 1, 0, -1, 1, 1, -1};
template <typename A, typename B>
string to_string(pair<A, B> p);
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);
string to_string(const string &s) { return '"' + s + '"'; }
string to_string(const char *s) { return to_string((string)s); }
string to_string(bool b) { return (b ? "true" : "false"); }
string to_string(char c) { return to_string(string(1, c)); }
string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (long long i = 0; i < static_cast<long long>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}
template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}
template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}
void debug() { cout << endl; }
template <typename Head, typename... Tail>
void debug(Head H, Tail... T) {}
long long power(long long a, long long b) {
  long long res = 1;
  while (b) {
    if (b & 1) res = (res * a) % mod;
    a = (a * a) % mod;
    b /= 2;
  }
  return res;
}
void solve() {
  long long n, m;
  cin >> n >> m;
  vector<long long> dp(n + 1);
  for (long long i = 1; i <= n; i++) {
    if (i == 1) {
      dp[1] = 2 * m;
    } else {
      long long alpha = (dp[i - 1] - power(m, i - 1) + mod) % mod;
      dp[i] = ((m * 2) * dp[i - 1] - alpha + mod) % mod;
    }
    debug(dp[i]);
  }
  cout << (dp[n] + mod) % mod << "\n";
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cout << fixed << setprecision(10);
  long long t = 1;
  for (long long i = 1; i <= t; i++) {
    solve();
  }
}

### Prompt

Please provide a Cpp coded solution to the problem described below:

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 long long mod = 1000000007LL;
const long long inf = 1e18;
inline long long max(long long a, int32_t b) { return a > b ? a : b; }
inline long long max(int32_t a, long long b) { return a > b ? a : b; }
inline long long min(long long a, int32_t b) { return a < b ? a : b; }
inline long long min(int32_t a, long long b) { return a < b ? a : b; }
long long d4_1[4] = {1, 0, -1, 0};
long long d4_2[4] = {0, 1, 0, -1};
long long d8_1[8] = {1, 1, 1, -1, -1, -1, 0, 0};
long long d8_2[8] = {0, -1, 1, 0, -1, 1, 1, -1};
template <typename A, typename B>
string to_string(pair<A, B> p);
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);
string to_string(const string &s) { return '"' + s + '"'; }
string to_string(const char *s) { return to_string((string)s); }
string to_string(bool b) { return (b ? "true" : "false"); }
string to_string(char c) { return to_string(string(1, c)); }
string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (long long i = 0; i < static_cast<long long>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}
template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}
template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}
void debug() { cout << endl; }
template <typename Head, typename... Tail>
void debug(Head H, Tail... T) {}
long long power(long long a, long long b) {
  long long res = 1;
  while (b) {
    if (b & 1) res = (res * a) % mod;
    a = (a * a) % mod;
    b /= 2;
  }
  return res;
}
void solve() {
  long long n, m;
  cin >> n >> m;
  vector<long long> dp(n + 1);
  for (long long i = 1; i <= n; i++) {
    if (i == 1) {
      dp[1] = 2 * m;
    } else {
      long long alpha = (dp[i - 1] - power(m, i - 1) + mod) % mod;
      dp[i] = ((m * 2) * dp[i - 1] - alpha + mod) % mod;
    }
    debug(dp[i]);
  }
  cout << (dp[n] + mod) % mod << "\n";
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cout << fixed << setprecision(10);
  long long t = 1;
  for (long long i = 1; i <= t; i++) {
    solve();
  }
}

```