# A - Odds of Oddness
def main():
    cnt = 0
    n = int(input())
    for i in range(1,n+1):
        if i % 2 != 0:
            cnt += 1
    print(cnt/n)

if __name__ ==  "__main__":
    main() def main():
    cnt = 0
    n = int(input())
    for i in range(1,n+1):
        if i % 2 != 0:
            cnt += 1
    print(cnt/n) main cnt = 0 cnt 0 n = int(input()) n int(input()) int input() input for i in range(1,n+1):
        if i % 2 != 0:
            cnt += 1
     i range(1,n+1) range 1 n+1 n 1 if i % 2 != 0:
            cnt += 1
     i % 2 != 0 i % 2 i 2 0 cnt += 1 cnt 1 print(cnt/n) print cnt/n cnt n if __name__ ==  "__main__":
    main() __name__ ==  "__main__" __name__ "__main__" main() main def main():
    cnt = 0
    n = int(input())
    for i in range(1,n+1):
        if i % 2 != 0:
            cnt += 1
    print(cnt/n) def main():
    cnt = 0
    n = int(input())
    for i in range(1,n+1):
        if i % 2 != 0:
            cnt += 1
    print(cnt/n) main
# A - Odds of Oddness
def main():
    cnt = 0
    n = int(input())
    for i in range(1,n+1):
        if i % 2 != 0:
            cnt += 1
    print(cnt/n)

if __name__ ==  "__main__":
    main()