#include <iostream>
#include <iomanip>
#include <vector>
#include <string>

class node
{ protected:
    string str;
    vector <node *> links;

  public:
    node(string s)
    { str = s; }

    static node * mk(string s)
    { return new node(s); }

    node * add(node * n)
    { links.push_back(n);
      return this; }

    string getname()
    { return str; }

    int getnumlinks()
    { return links.size(); }

    node * getlink(int i)
    { return links[i]; }
};

void print(node * n, int depth = 0)
{ cout << setw(depth*5) << " " << n->getname() << "\n";
  int num = n->getnumlinks();
  for (int i = 0; i < num; i += 1)
    print(n->getlink(i), depth+1); }

void main()
{ node * t1 = node::mk("ant")
                             ->add(node::mk("bat")
                                                  ->add(node::mk("egg")
                                                                       ->add(node::mk("kit"))
                                                                       ->add(node::mk("log")))
                                                  ->add(node::mk("fig"))
                                                  ->add(node::mk("gat")
                                                                       ->add(node::mk("map"))
                                                                       ->add(node::mk("nut"))
                                                                       ->add(node::mk("old"))
                                                                       ->add(node::mk("pig"))))
                             ->add(node::mk("cat")
                                                  ->add(node::mk("hat")))
                             ->add(node::mk("dog")
                                                  ->add(node::mk("ink")
                                                                       ->add(node::mk("qat"))
                                                                       ->add(node::mk("rat")))
                                                  ->add(node::mk("jug")
                                                                       ->add(node::mk("sud"))
                                                                       ->add(node::mk("tip"))));
  print(t1); }