import java.math.BigInteger;
import java.util.Arrays;
import java.util.Scanner;

class Main {
	public static void main(String[] args) throws Exception {
		new Main().run();
	}
	
	void run() {
		Scanner sc=new Scanner(System.in);
		int N=sc.nextInt();
		BigInteger a=BigInteger.valueOf(10).pow(N);
		a=a.divide(BigInteger.valueOf(7));
		System.out.println("0."+a);
	}
	
	static void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}
	
}