#include <iostream>
#include <algorithm>
#include <random>
using namespace std;

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