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