Problem: Given is an integer N.

Takahashi chooses an integer a from the positive integers not greater than N with equal probability.

Find the probability that a is odd.

Constraints

* 1 \leq N \leq 100

Input

Input is given from Standard Input in the following format:


N


Output

Print the probability that a is odd. Your output will be considered correct when its absolute or relative error from the judge's output is at most 10^{-6}.

Examples

Input

4


Output

0.5000000000


Input

5


Output

0.6000000000


Input

1


Output

1.0000000000

Solution (in JAVA):

Solution:
import java.util.Scanner;
public class Main
{
	public static void main(String[] args)
	{
		Scanner sc = new Scanner(System.in);
		double num = sc.nextInt();

		if(num%2 == 0)
		{
			System.out.println(((num/2)/num));
		}
		else
		{
			System.out.println((((int)num/2+1))/num);
		}
	}
}