Score : 100 points
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.
Input is given from Standard Input in the following format:
N
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}.
4
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.
5
0.6000000000
1
1.0000000000