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

    if N % 2 == 0:
        ans = 1 / 2
    else:
        ans = (N // 2 + 1) / N

    print(f"{ans:.10f}")


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

    if N % 2 == 0:
        ans = 1 / 2
    else:
        ans = (N // 2 + 1) / N

    print(f"{ans:.10f}") main N = int(input()) N int(input()) int input() input if N % 2 == 0:
        ans = 1 / 2
    else:
        ans = (N // 2 + 1) / N

     N % 2 == 0 N % 2 N 2 0 ans = 1 / 2 ans 1 / 2 1 2 ans = (N // 2 + 1) / N ans (N // 2 + 1) / N N // 2 + 1 N // 2 N 2 1 N print(f"{ans:.10f}") print f"{ans:.10f}" if __name__ == "__main__":
    main() __name__ == "__main__" __name__ "__main__" main() main def main():
    N = int(input())

    if N % 2 == 0:
        ans = 1 / 2
    else:
        ans = (N // 2 + 1) / N

    print(f"{ans:.10f}") def main():
    N = int(input())

    if N % 2 == 0:
        ans = 1 / 2
    else:
        ans = (N // 2 + 1) / N

    print(f"{ans:.10f}") main
def main():
    N = int(input())

    if N % 2 == 0:
        ans = 1 / 2
    else:
        ans = (N // 2 + 1) / N

    print(f"{ans:.10f}")


if __name__ == "__main__":
    main()
