#include <bits/stdc++.h>
using namespace std;

int main() {
	int n; cin >> n;
	if (n == 0) {
		cout << 0 << endl;
		return 0;
	}
	string s = "142857";
	cout << "0.";
	for (int i = 0; i < n; i++) {
		cout << s[i%6];
	}
	cout << endl;
}