#include <bits/stdc++.h>
using namespace std;
#define int long long
#define ld long double
#define show(x,y) cout << y << " " << #x << endl;
#define show2(x,y,i,j) cout << y << " " << #x << " " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) cout << y << " " << #x << " " << j << " " << #i << " " << q << " " << #p << endl;
#define show4(x,y) for(auto it:y) cout << it << " "; cout << #x << endl;
typedef pair<long long,long long>pii;
typedef pair<int,pii>pi2;
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
void solve(){
int n,k;
cin >> n >> k;
int arr[n];
for(int x=0;x<n;x++){
arr[x]=x+1;
}
int counter=0;
do{
int cnt=0;
for(int x=1;x<n;x++){
if(arr[x]<arr[x-1]) cnt++;
}
if(cnt==k-1) counter++;
}while(next_permutation(arr,arr+n));
cout << counter;
}
int32_t main(){
ios::sync_with_stdio(0);
cin.tie(0);
int t=1;
//freopen("in.txt","r",stdin);
//cin >> t;
while(t--){
solve();
}
}
