Problem:
Score : 100 points

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}.

Sample Input 1

4

Sample Output 1

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.

Sample Input 2

5

Sample Output 2

0.6000000000

Sample Input 3

1

Sample Output 3

1.0000000000

Solution in Ruby (2.3.3) (judge verdict: Runtime Error)

n = gets.to_i
num = arr[] 
even = arr[]
num = 1..n
i = 0
for(i <= n) 
  num_num = num[i]
  if(num_num % 2 == 0) 
    even.push(num_num)
    i =+1
  else
  i =+1
end
num_max = num.length
even_max = even.length
puts "#{even_max % num_max}"