import java.math.BigDecimal;
import java.math.RoundingMode;
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();
		BigDecimal p=new BigDecimal(String.valueOf((long)Math.pow(10, n)));
		BigDecimal k = new BigDecimal(String.valueOf((long)Math.pow(10, n)/7));
		System.out.println(k.divide(p,30,RoundingMode.DOWN));
	}
}