template<typename T,
         int IdFrom=0,
         typename OpLs=less<T>,
         typename OpEq=equal_to<T>>
struct Dctz {
    static OpLs ls;
    static OpEq eq;
    vector<T> x;
    void clear() { x.clear(); }
    void add(T v) { x.push_back(v); }
    void init() { 
        sort(x.begin(),x.end(),ls); 
        x.erase(unique(x.begin(),x.end(),eq),x.end()); 
    }
    int size() { return x.size(); }
    int id(const T &v) { 
        return lower_bound(x.begin(),x.end(),v,ls)-x.begin()+IdFrom; }
    T& operator[](int id) { return x[id-IdFrom]; };
};
Dctz<> dc;