#include <bits/stdc++.h>
using namespace std;

#ifdef _DEBUG
#include "_DEBUG.hpp"
#endif
#define int long long
const long long inf = 2e18;
const int mod = 1e9 + 7;

template <typename T>
istream &operator>>(istream &is, vector<T> &v) {
  for (T &in : v) is >> in;
  return is;
}

template <class T>
vector<T> make_vec(size_t a) {
  return vector<T>(a);
}

template <class T, class... Ts>
auto make_vec(size_t a, Ts... ts) {
  return vector<decltype(make_vec<T>(ts...))>(a, make_vec<T>(ts...));
}

template <class T, class V>
typename enable_if<is_class<T>::value == 0>::type fill(T &t, const V &v) {
  t = v;
}

template <class T, class V>
typename enable_if<is_class<T>::value != 0>::type fill(T &t, const V &v) {
  for (auto &e : t) fill(e, v);
}

int power(int n, int p) {
  int r = 1;
  for (; p > 0; p >>= 1) {
    if (p & 1ll) r = r * n % mod;
    n = n * n % mod;
  }
  return r;
}

signed main() {
  int n, k;
  cin >> n >> k;

  int ans = n * (power(n, k) - power(n - 1, k) + mod) % mod;
  cout << ans << endl;

  return 0;
}