# coding: utf-8
# Your code here!

n=int(input())

if n%2==0:
    a=n/2
else:
    a=n//2+1

print(a/n) n=int(input()) n int(input()) int input() input if n%2==0:
    a=n/2
else:
    a=n//2+1 n%2==0 n%2 n 2 0 a=n/2 a n/2 n 2 a=n//2+1 a n//2+1 n//2 n 2 1 print(a/n) print a/n a n a=n/2 n/2 a n=int(input()) int(input()) n a=n//2+1 n//2+1 a
# coding: utf-8
# Your code here!

n=int(input())

if n%2==0:
    a=n/2
else:
    a=n//2+1

print(a/n)