# -*- coding: utf-8 -*-

def main():

    N = int(input())

    num = 0

    for i in range(N + 1):
        if i % 2 > 0:
            num += 1
    
    ans = num / N

    print(ans)


if __name__ == "__main__":
    main() def main():

    N = int(input())

    num = 0

    for i in range(N + 1):
        if i % 2 > 0:
            num += 1
    
    ans = num / N

    print(ans) main N = int(input()) N int(input()) int input() input num = 0 num 0 for i in range(N + 1):
        if i % 2 > 0:
            num += 1
    
     i range(N + 1) range N + 1 N 1 if i % 2 > 0:
            num += 1
    
     i % 2 > 0 i % 2 i 2 0 num += 1 num 1 ans = num / N ans num / N num N print(ans) print ans if __name__ == "__main__":
    main() __name__ == "__main__" __name__ "__main__" main() main def main():

    N = int(input())

    num = 0

    for i in range(N + 1):
        if i % 2 > 0:
            num += 1
    
    ans = num / N

    print(ans) def main():

    N = int(input())

    num = 0

    for i in range(N + 1):
        if i % 2 > 0:
            num += 1
    
    ans = num / N

    print(ans) main
# -*- coding: utf-8 -*-

def main():

    N = int(input())

    num = 0

    for i in range(N + 1):
        if i % 2 > 0:
            num += 1
    
    ans = num / N

    print(ans)


if __name__ == "__main__":
    main()