Pascal Triangle

#include <iostream>

#include <cstdio>

#include <cstring>

#include <string>

using namespace std;

#define siz 1005

typedef long long ll;

ll a[siz][siz];



void pascal(){

    ll i,j;

    a[0][0]=1;

    a[1][0]=a[1][1]=1;

    for(i=2;i<=1000;i++){

        for(j=1;j<=i;j++){

            if(j==1||j==i) a[i][j]=1;

            else a[i][j]=a[i-1][j-1]+a[i-1][j];

        }

    }

}



int main()

{

    pascal();

    ll n,r;

    #ifndef ONLINE_JUDGE

    freopen("input.txt","r",stdin);

    #endif

    while(cin>>n>>r){

        if(n==0&&r==0) break;

        cout<<n<<" things taken "<<r<<" at a time is "<<a[n+1][r+1]<<" exactly."<<endl;

    }

    return 0;

}