template<typename T>
class Cos
{
private:
    vector<T> chestii;
public:
    Cos() = default;
    /*Cos(Cos<T>& ot)
    {
        chestii.size() = ot.size();
        for (int i = 0; i < chestii.size(); i++)
        {
            chestii[i] = ot.chestii[i];
        }
    }*/
    Cos& operator+(const T& elem)
    {
        chestii.pb(elem);
        return *this;
    }
    Cos& undo()
    {
        chestii.erase(chestii.begin() + chestii.size()-1);
        return *this;
    }
    void operator=(const Cos<T>& ot)
    {
        chestii = ot.chestii;
    }
    void tipareste(ostream& s)
    {
        for (unsigned int i = 0; i < chestii.size(); i++)
            s << chestii[i]<<"  ";
    }

};