import math

n = int(input())

answer = (n - math.floor(n / 2)) / n

print(answer)

# nums = list(range(1, n + 1))
# 
# odds = [x for x in nums if x % 2 == 1]
# 
# if len(nums) % 2 == 0:
#     print(0.5)
# else:
#     print(len(odds) / len(nums)) import math math n = int(input()) n int(input()) int input() input answer = (n - math.floor(n / 2)) / n answer (n - math.floor(n / 2)) / n n - math.floor(n / 2) n math.floor(n / 2) math.floor math floor n / 2 n 2 n print(answer) print answer n = int(input()) int(input()) n answer = (n - math.floor(n / 2)) / n (n - math.floor(n / 2)) / n answer
import math

n = int(input())

answer = (n - math.floor(n / 2)) / n

print(answer)

# nums = list(range(1, n + 1))
# 
# odds = [x for x in nums if x % 2 == 1]
# 
# if len(nums) % 2 == 0:
#     print(0.5)
# else:
#     print(len(odds) / len(nums))
