import java.util.Scanner;
public class Main{
  public static void main(String[]args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    double m = 0;

    if(1<=n && n<=100){
      if(n%2==0){
        m = (double)(n/2)/n;
        System.out.println(m);
      }
      if(n%2==1){
        m = (double)((n+1)/2)/n;
        System.out.println(m);
      }
    }
  }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz