#include<stdio.h>

void main()
{
  int i, n, f;

  printf("\n Enter n: ");
  scanf("%d", &n);

  f=1;
  i=n;
  for(;;)      
    {
      if(i<1)
	break;

      f=f*i;
      i--;

    }

  printf("\n %d! = %d\n", n, f);


}