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