import java.io.*;
import java.util.Scanner;


public class Main_yukicoder746 {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		int n = sc.nextInt();

		if (n == 0) {
			pr.println(0);
		} else {
			String s7 = "142857";
			
			StringBuilder sb = new StringBuilder();
			sb.append("0.");
			for (int i = 0; i < n; i++) {
				sb.append(s7.charAt(i % s7.length()));
			}
			
			pr.println(sb);
		}
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		pr = new Printer(System.out);
			
		solve();
			
		pr.close();
		sc.close();
	}

	static class Printer extends PrintWriter {
		Printer(OutputStream out) {
			super(out);
		}
	}
}