N=int(input())
if 1<=N<=100:
    if N%2==1:
        print((N+1)/(2*N))
    elif N%2==0:
        print(1/2) N=int(input()) N int(input()) int input() input if 1<=N<=100:
    if N%2==1:
        print((N+1)/(2*N))
    elif N%2==0:
        print(1/2) 1<=N<=100 1<=N 1 N 100 if N%2==1:
        print((N+1)/(2*N))
    elif N%2==0:
        print(1/2) 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 elif N%2==0:
        print(1/2) N%2==0 N%2 N 2 0 print(1/2) print 1/2 1 2 N=int(input()) int(input()) N
N=int(input())
if 1<=N<=100:
    if N%2==1:
        print((N+1)/(2*N))
    elif N%2==0:
        print(1/2)