# from collections import Counter
# n = int(input())
# li = list(map(int, input().split()))
# a, b = map(int, input().split())
# a = int(input())
n = int(input())
odd = (n+1)//2
even = n//2
print(odd/(odd+even)) n = int(input()) n int(input()) int input() input odd = (n+1)//2 odd (n+1)//2 n+1 n 1 2 even = n//2 even n//2 n 2 print(odd/(odd+even)) print odd/(odd+even) odd odd+even odd even odd = (n+1)//2 (n+1)//2 odd n = int(input()) int(input()) n even = n//2 n//2 even
# from collections import Counter
# n = int(input())
# li = list(map(int, input().split()))
# a, b = map(int, input().split())
# a = int(input())
n = int(input())
odd = (n+1)//2
even = n//2
print(odd/(odd+even))
