#include<iostream>
#include<vector>

using namespace std;
template<class t>
class node
{
public:
  t dato;
  node<t> * pson[2]; //2 punteros a sus hijos
  node(t d)
  {
    dato = d;
    pson[0] = pson[1] = NULL;
  }	
};

template<class t>
class binary_tree
{
  node<t> * proot; 

public:
  binary_tree()
  {
    proot = NULL;
  }

  void add (t dat)
  {
		node <t> **p ;
		if (find(dat,p))
			return;
		*p = new node<t>(dat);
  }

  bool find(t dat,node<t> ** &p)
  {
    p =&proot;
    while(*p)
      {
		if((*p)->dato==dat)return true;
		p= &((*p)->pson[(*p)->dato<dat]);
      }
    return false;
  }

  void preorden(node<t> * p = proot )
  {

	  if(!p) return;
	  cout<<p->dato<<endl;
	  preorden(p->pson[0]);
	  preorden(p->pson[1]);
  }
		
};