import math

def main():
    n=int(input())
    print(math.ceil(n/2)/n)
                
if __name__ == '__main__':
    main() import math math def main():
    n=int(input())
    print(math.ceil(n/2)/n)
                 main n=int(input()) n int(input()) int input() input 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 if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main def main():
    n=int(input())
    print(math.ceil(n/2)/n)
                 def main():
    n=int(input())
    print(math.ceil(n/2)/n)
                 main
import math

def main():
    n=int(input())
    print(math.ceil(n/2)/n)
                
if __name__ == '__main__':
    main()