#include <bits/stdc++.h>
using namespace std;
const int mod=1000000007;
long long A(int n,int k)
{
long long sum1=1;
for (int i=n;i>n-k;i--) sum1*=i, sum1%=mod;
return sum1;
}
int main()
{
int n, k;
cin >> n >> k;
cout<<A(n-k+1,n-k+1)*A(k,k)%mod<<endl;
return 0;
}```