#include <iostream>
#include <string>
using namespace std;

int main() {
	int N;
	string tmp = "142857";
	cin >> N;
	if (N == 0) cout << 0;
	else {
		cout << "0.";
		for (int i = 0; i < N / 6; ++i) cout << tmp;
		for (int i = 0; i < N % 6; ++i) cout << tmp[i];
	}
}