/*  This Code is Submitted by wywcgs for Problem 1331 on 2005-10-03 at 09:46:30 */ 
#include <stdio.h>
#define  MAX  100000

int main()
{
	double hang[MAX], sum = 0;
	long i, n;

	for (i = 1; i < MAX; i++) {
		sum += (double)1 / (2*i);
		hang[i] = sum;
	}
	printf("# Cards  Overhang\n");
	while(scanf("%ld", &n) == 1) {
		printf("%5ld%10.3lf\n", n, hang[n]);
	}
	
	return 0;
}