import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int num = scan.nextInt();
        double result = 0.0;
        if(num%2 == 0) {
            result = 1.0/2.0;
            System.out.println(result);
        }else if(num == 1) {
            System.out.println(1.0);
        } else {
            result = ((num-1)/2+1)/(double)num;
            System.out.println(result);
        }
    }

}

/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