Problem Statement

Given is an integer $N$.

Takahashi chooses an integer $a$ from the positive integers not greater than $N$ with equal probability.

Find the probability that $a$ is odd.

Constraints

• $1 \leq N \leq 100$

Input

Input is given from Standard Input in the following format:

N

Output

Print the probability that $a$ is odd. Your output will be considered correct when its absolute or relative error from the judge's output is at most $10^{-6}$.