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.*;
class Main
{
	public static void main(String[] args) 	
	{
		Scanner scan=new Scanner(System.in) ;
		int N=scan.nextInt();
		float prob, odd;
		
		if(N>=1 && N<=100)
		{
			if(N%2==0)
				prob=0.5f;
			else
			{
				odd=(N/2)+1;
				prob=odd/N;
			}
			System.out.println(prob);
		}
	}
}