import sys, math
input = sys.stdin.readline
rs = lambda: input().strip()
ri = lambda: int(input())
rl = lambda: list(map(int, input().split()))
mod = 10**9 + 7

N = ri()

print(math.ceil(N / 2) / N)
 import sys, math sys math input = sys.stdin.readline input sys.stdin.readline sys.stdin sys stdin readline rs = lambda: input().strip() rs lambda: input().strip() input().strip() ().strip () input strip ri = lambda: int(input()) ri lambda: int(input()) int(input()) int input() input rl = lambda: list(map(int, input().split())) rl lambda: list(map(int, input().split())) list(map(int, input().split())) list map(int, input().split()) map int input().split() ().split () input split mod = 10**9 + 7 mod 10**9 + 7 10**9 10 9 7 N = ri() N ri() ri print(math.ceil(N / 2) / N) print math.ceil(N / 2) / N math.ceil(N / 2) math.ceil math ceil N / 2 N 2 N rs = lambda: input().strip() lambda: input().strip() rs ri = lambda: int(input()) lambda: int(input()) ri mod = 10**9 + 7 10**9 + 7 mod N = ri() ri() N input = sys.stdin.readline sys.stdin.readline input rl = lambda: list(map(int, input().split())) lambda: list(map(int, input().split())) rl
import sys, math
input = sys.stdin.readline
rs = lambda: input().strip()
ri = lambda: int(input())
rl = lambda: list(map(int, input().split()))
mod = 10**9 + 7

N = ri()

print(math.ceil(N / 2) / N)

