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;


class Main{
 public static void main(String[] args){
  Scanner scanner = new Scanner(System.in);
  int N = scanner.nextInt();
  

 
int i = 0;
for(int a = 1;a <= N; a++){
  if(a % 2 == 1){
    i++;
  }else{
    continue;
  }
}

  System.out.println( (double)i/N );
  
  
}
}