import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String inputStr = sc.next();
        int input = Integer.parseInt(inputStr);
        
        int oddCount = input % 2 == 0 ? input / 2 : (input / 2) + 1;
        String oddCountStr = Integer.toString(oddCount);
        
        double rate = (Double.parseDouble(oddCountStr) / Double.parseDouble(inputStr));

        System.out.println(rate);
    }
}
/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