import java.util.*;
import java.util.stream.*;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int mod = (int)1e9 + 7;
        int n = sc.nextInt();
        if (n == 1) {
            System.out.println(1);
        } else if (n % 2 == 0) {
            System.out.println(0.5);
        } else {
            System.out.println((n/2+1)/(double)n);
        }
    }

}

/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