#!/usr/bin/env python3
# -*- coding: utf-8 -*-
n = int(input())
a=n//2+(n%2)
print(a/n) n = int(input()) n int(input()) int input() input a=n//2+(n%2) a n//2+(n%2) n//2 n 2 n%2 n 2 print(a/n) print a/n a n n = int(input()) int(input()) n a=n//2+(n%2) n//2+(n%2) a
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
n = int(input())
a=n//2+(n%2)
print(a/n)
