#include <iostream>
#include <cstdlib>

using namespace std;

int main(void)
{
   int n, r;
   cout << "dar n y r\n";
   cin >> n >> r;

   int k= 1;
   int prod= 1;

   while (k<=r)
      {
       prod= prod * (n-(k-1)) / k;
       k= k+1;
      }
   cout << "coef(" << n << "," << r << ")= " << prod << endl;
   return EXIT_SUCCESS;
}