Description

Read in $n$ and compute the value of $S = 1 - \frac{1}{2} + \frac{1}{3} - \frac{1}{4} + \frac{1}{5} - \frac{1}{6} + \ldots + \frac{1}{n}$. Output the result left-aligned, rounded to 10 decimal places.

Input Format

Input a number $n$.

Output Format

Output $S$.

6

0.6166666667

Hint

Data Range:
1 <= $n$ <= 100

Source

CodesOnline