import java.util.Scanner;

public class Main {

	@SuppressWarnings("resource")
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);
		int n=scanner.nextInt();
		long p=(long) Math.pow(10, n);
		long k=p/7;
		System.out.println((double)k/p);
	}
}