#include <cstdio>
#include <algorithm>
const int p = 1000000007;
using namespace std;
int f(int x, int y)
{
return y & 1 ? (long long)f(x, y ^ 1)*x%p : y ? f((long long)x*x%p, y >> 1) : 1;
}
int fac[1000001];
int inv[1000001];
int main()
{
int i, j, n, m, r = 0;
scanf("%d%d", &n, &m);
fac[0] = 1;
for (i = 1; i <= n + 1; i++) fac[i] = (long long)fac[i - 1] * i % p;
inv[n + 1] = f(fac[n + 1], p - 2);
for (i = n + 1; i >= 1; i--) inv[i - 1] = (long long)inv[i] * i % p;
for (i = 0; i < n - m; i++)
{
j = fac[n - i];
j = (long long)j * fac[n - m + 1] % p;
j = (long long)j * inv[n - m - i - 1] % p;
j = (long long)j * f(i + 2, p - 2) % p;
r = (r + j) % p;
}
printf("%d", r);
}
