#include<stdio.h>

void run(void){
  int n;
  scanf("%d",&n);
  if(n<=4){
    printf("0\n");
    return;
  }

  double p=1.0;
  int i;
  for(i=0;i<5;i++){
    p*=(double)(n-i)/(99-i);
  }
  printf("%.6lf\n",12*p);
  return;
}

int main(void){
  run();
  return 0;
}