# input
N = int(input())

if N % 2 == 0:
    print(0.5)
elif N == 1:
    print(1)
else:
    c = (N - 1) // 2
    print((c + 1) / N) N = int(input()) N int(input()) int input() input if N % 2 == 0:
    print(0.5)
elif N == 1:
    print(1)
else:
    c = (N - 1) // 2
    print((c + 1) / N) N % 2 == 0 N % 2 N 2 0 print(0.5) print 0.5 elif N == 1:
    print(1) N == 1 N 1 print(1) print 1 c = (N - 1) // 2 c (N - 1) // 2 N - 1 N 1 2 print((c + 1) / N) print (c + 1) / N c + 1 c 1 N c = (N - 1) // 2 (N - 1) // 2 c N = int(input()) int(input()) N
# input
N = int(input())

if N % 2 == 0:
    print(0.5)
elif N == 1:
    print(1)
else:
    c = (N - 1) // 2
    print((c + 1) / N)