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 Python (3.8.2) (judge verdict: Accepted)

# Coding is about expressing your feeling, and
# there is always a better way to express your feeling_feelme
import sys
import math
# sys.stdin=open('input.txt','r')
# sys.stdout=open('output2.txt','w')
from sys import stdin,stdout
from collections import deque,defaultdict
from math import ceil,floor,inf,sqrt,factorial,gcd,log2
from copy import deepcopy
ii1=lambda:int(stdin.readline().strip())
is1=lambda:stdin.readline().strip()
iia=lambda:list(map(int,stdin.readline().strip().split()))
isa=lambda:stdin.readline().strip().split()
mod=int(1e9 + 7)

n=ii1()
if n==1:
    print(1)
elif n%2==0:
    print(1/2)
else:
    print((n//2 +1)/n)