#include<iostream>
using namespace std;

int fact(int n){

   int ans = 1;
   for(int i =2;i<=n;i++){
    ans = ans * i;
   }
     return ans;

}

int nCr(int n,int r){
    return fact(n)/(fact(n-r)*fact(r));
}

int main(){

    int n,r;
    cin>>n>>r;

    int ans = nCr(n,r);
    cout<<ans;


    return 0;
}