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 scanner = new Scanner(System.in);
		Integer n = Integer.valueOf(scanner.nextInt());
		Integer oddNum = (n / 2) + (n % 2);
		System.out.println((float)oddNum / (float)n);
	}

}