n=int(input())
if n%2==1:
    print((n+1)/(2*n))
else:
    print(n/(2*n)) n=int(input()) n int(input()) int input() input if n%2==1:
    print((n+1)/(2*n))
else:
    print(n/(2*n)) n%2==1 n%2 n 2 1 print((n+1)/(2*n)) print (n+1)/(2*n) n+1 n 1 2*n 2 n print(n/(2*n)) print n/(2*n) n 2*n 2 n n=int(input()) int(input()) n
n=int(input())
if n%2==1:
    print((n+1)/(2*n))
else:
    print(n/(2*n))