#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
#include <deque>
#include <queue>
#include <array>
#include <set>
#include <map>
#include <cmath>
#include <algorithm>
#include <numeric>
#include <cassert>
#include <utility>
#include <functional>
#include <bitset>
#include <cstdint>

using namespace std;
using lli = long long int;
using i64 = int64_t;
template<class T, class U> void init_n(vector<T>& v, size_t n, U x) 
{ v = vector<T>(n, x); }
template<class T> void init_n(vector<T>& v, size_t n) { init_n(v, n, T()); }
template<class T> void read_n(vector<T>& v, size_t n, size_t o = 0) 
{ v = vector<T>(n+o); for (size_t i=o; i<n+o; ++i) cin >> v[i]; }
template<class T> void read_n(T a[], size_t n, size_t o = 0)
{ for (size_t i=o; i<n+o; ++i) cin >> a[i]; }
template<class T> T gabs(const T& x) { return max(x, -x); }
#define abs gabs

const i64 mod = 1e9 + 7;
i64 fact_memo[200001];
i64 fact(i64 x) {
  if (x == 0) return 1;
  if (fact_memo[x]) return fact_memo[x];
  return fact_memo[x] = x * fact(x - 1) % mod;
}
i64 ipow(i64 a, i64 b) {
  return (b & 1 ? a : 1) * (b > 1 ? ipow(a * a % mod, b >> 1) : 1) % mod;
}
i64 fact_inv(i64 x) {
  return ipow(fact(x), mod - 2);
}
i64 perm(i64 a, i64 b) {
  return fact(a) * fact_inv(a - b) % mod;
}
i64 conb(i64 a, i64 b) {
  return fact(a) * fact_inv(b) % mod * fact_inv(a - b) % mod;
}
int main() {
  i64 n, k;
  cin >> n >> k;
  i64 ans = 0;
  for (i64 x = 1; x <= n; ++x) {
    ans = (ans 
        + x * (
          perm(n, k)
          - k * perm(n - 1, k - 1) % mod
          + ((x < n || k ==1) ? k * (k - 1) / 2 % mod * perm(n - 2, k - 2) % mod : 0)
          + 2 * mod) % mod
        ) % mod;
  }
  cout << ans << '\n';

  return 0;
}