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.*;
public class Main{


public static void main(String[] args){
Scanner obj=new Scanner(System.in);
int n=obj.nextInt();
float o=0;
float ans=0;
for(int i=1;i<=n;i++){

if(i%2!=0){
o++;
}

}

ans=o/n;
System.out.println(ans);






}




}