#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<pii,int> ppii;
typedef pair<ll,ll> pll;
typedef tuple<ll,ll,ll> tl;
ll mod=1000000007;
ll gcd(ll a,ll b){
  if(a<b)swap(a,b);
  if(a%b==0)return b;
  return gcd(b,a%b);
}
ll lcm(ll a,ll b){
  ll ret=a*b;
  ll u=gcd(a,b);
  return ret/u;
}
ll gyaku(ll n){
  ll u=mod-2;
  ll ret=1;
  ll now=n;
  while(u>0){
    if(u%2){
      ret*=now;
      ret%=mod;
    }
    now*=now;
    now%=mod;
    u/=2;
  }
  return ret;
}
ll nck(ll n,ll k){
  ll ret=1;
  for(int i=0;i<k;i++){
    ret*=n-i;
    ret%=mod;
    ret*=gyaku(i+1);
    ret%=mod;
  }
  return ret;
}
ll npk(ll n,ll k){
  ll ret=1;
  for(int i=0;i<k;i++){
    ret*=n-i;
    ret%=mod;
  }
  return ret;
}
ll kai(ll n,ll k){
  ll ret=1;
  ll now=n;
  while(k>0){
    if(k%2){
      ret*=now;
      ret%=mod;
    }
    now*=now;
    now%=mod;
    k/=2;
  }
  return ret;
}
int main(){
  ll n,k;cin>>n>>k;
  if(n==1){
    cout<<0<<endl;
    return 0;
  }
  ll sum=0;
  if(k<n){
    sum=npk(n-1,k);
  }
  ll u=0;
  if(k>1){
    u=nck(n-2,k-2);
  for(int i=1;i<=k;i++){
    u*=i;
    u%=mod;
  }
  u*=gyaku(2);
  u%=mod;
  }
  ll ans=0;
  for(int i=1;i<n;i++)ans+=i;
  ans*=sum+u;
  ans%=mod;
  ans+=n*sum;
  cout<<ans%mod<<endl;
}