
import java.io.IOException;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) throws IOException {

		Scanner scan = new Scanner(System.in);

		double n = scan.nextDouble();

		double output = 0;

		if (n == 1) {

			output = 1;

		} else if (n == 2) {

			output = 0.5;
		}

		if (n % 2 == 1) {

			output = ((int) (n / 2) + 1) / n;

		} else {

			output = (n / 2) / n;

		}

		System.out.println(output);
	}

}
/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