struct node
{ string data;
  node * left, * right;
  node(string a)
  { data = a;
     left = NULL;
     right = NULL; } };

class tree
{ protected:
     node * root;
   public:
     tree()
     { root = NULL; }
     
      void insert(string a, node * & T)
      { if (T == NULL)
            T = new node(a);
         if (a < T->data)
             insert(a, T->left);
         else
             insert(a, T->right); }

      void insert(string a)
      { insert(a, root); }

      bool find(string a, node * T)
      {  if (T == NULL)
             return false;
          if (a == T->data)
             return true;
          else if (a < T->data)
             return find(a, T->left);
          else
             return find(a, T->right); }

      bool find(string a)
      { return find(a, root); }