N=int(input())

K=(N+1)//2
print(K/N) N=int(input()) N int(input()) int input() input K=(N+1)//2 K (N+1)//2 N+1 N 1 2 print(K/N) print K/N K N K=(N+1)//2 (N+1)//2 K N=int(input()) int(input()) N
N=int(input())

K=(N+1)//2
print(K/N)