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:

public class Main {
    public static void main(String[] args) {

	int cnt = 0;
	double out;
       
	int  n = new java.util.Scanner(System.in).nextInt();


	for(int i = n; i >= 1; i--) {
	    if(i % 2 != 0) {
		cnt++;
	
	    }
	}

	out = (double)cnt / (double)n;
	System.out.printf("%.8f", out);
    }
}