import math


def main():
    N = int(input())

    if N % 2 == 0:
        print("{:.11f}".format((N / 2) / N))
    else:
        print("{:.11f}".format(math.ceil(N / 2) / N))


if __name__ == "__main__":
    main() import math math def main():
    N = int(input())

    if N % 2 == 0:
        print("{:.11f}".format((N / 2) / N))
    else:
        print("{:.11f}".format(math.ceil(N / 2) / N)) main N = int(input()) N int(input()) int input() input if N % 2 == 0:
        print("{:.11f}".format((N / 2) / N))
    else:
        print("{:.11f}".format(math.ceil(N / 2) / N)) N % 2 == 0 N % 2 N 2 0 print("{:.11f}".format((N / 2) / N)) print "{:.11f}".format((N / 2) / N) "{:.11f}".format "{:.11f}" format (N / 2) / N N / 2 N 2 N print("{:.11f}".format(math.ceil(N / 2) / N)) print "{:.11f}".format(math.ceil(N / 2) / N) "{:.11f}".format "{:.11f}" format math.ceil(N / 2) / N math.ceil(N / 2) math.ceil math ceil N / 2 N 2 N if __name__ == "__main__":
    main() __name__ == "__main__" __name__ "__main__" main() main def main():
    N = int(input())

    if N % 2 == 0:
        print("{:.11f}".format((N / 2) / N))
    else:
        print("{:.11f}".format(math.ceil(N / 2) / N)) def main():
    N = int(input())

    if N % 2 == 0:
        print("{:.11f}".format((N / 2) / N))
    else:
        print("{:.11f}".format(math.ceil(N / 2) / N)) main
import math


def main():
    N = int(input())

    if N % 2 == 0:
        print("{:.11f}".format((N / 2) / N))
    else:
        print("{:.11f}".format(math.ceil(N / 2) / N))


if __name__ == "__main__":
    main()
