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 scan = new Scanner(System.in);

		int N = scan.nextInt();

	    int oddcnt = N-N/2;

	    double prob = (double)oddcnt/(double)N;

	    System.out.println(prob);

	}
}