#include <stdio.h>
#include <stdlib.h>
long int numOfRookConfig(int n);
int main()
{
  int n = 8;
  printf("Number of Configuration = %d \n", numOfRookConfig(n));
  
  return 0;
}
long int numOfRookConfig(int n)
{
  /* Placing a Rook at any position blocks one row and one column.
   * So, only one rook can be placed in each row or column.
   * Say, a rook is placed at position 3,4 , then no other rook can be placed in both row 3 and row 4.This can be considered as decreasing the matrix by size 1.
   * If we start by placing a rook in first column of matrix there are n ways to do that.
   * It turns out to be factorial.
   */
  if(n==1)
    return 1;
  return n * numOfRookConfig(n-1);
}