#include<iostream>
#include<string>
using namespace std;
int main() {
	int  N; cin >> N;
	string s = "142857";
	cout << "0.";
	for (int i = 0; i < N / 6; i++)
		cout << s;
	for (int i = 0; i < N % 6; i++)
		cout << s[i];
	cout << endl;
	return 0;
}