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

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