#include"stdio.h"
int main()
{ int n,i;
  double ans;
  printf("Cards  Overhang\n");
  while(scanf("%d",&n)!=EOF)
  { ans=0.0;
	for(i=1;i<=n;i++)
		ans=ans+1.0/(2*i);
	printf("%5d     %.3lf\n",n,ans);
  }
  return 0;
}