/*    C Main program using assembly language
      function Factorial to calculate P(N,R)   */

main ()
{

  int     N, R, NPR, NMinusR, Factorial();

  printf ("Enter values for N and R\n");
  scanf ("%d%d", &N, &R);
  NMinusR = N - R;
  NPR = Factorial (&N) / Factorial (&NMinusR); 
  printf ("Number of permutations = %d\n", NPR);
}