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}.

-----Sample Input-----
4

-----Sample Output-----
0.5000000000

There are four positive integers not greater than 4: 1, 2, 3, and 4. Among them, we have two odd numbers: 1 and 3. Thus, the answer is $\frac{2}{4} = 0.5$.

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