#include<stdio.h>
int main()
{
    int n,k,i,m=1;
    double sum;
    while(~scanf("%d",&n))
    {
      k=1;
      for(i=1;i<=n;i++)
      {
        k=2*i;
        sum=sum+1/(k*1.0);
      }
      if(m==1)
      {
      printf("Cards  Overhang\n");
      m=0;
      }
      printf("%5d%10.3lf\n",n,sum);
      sum=0;
    }
    return 0;
}