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

const int _binop=1, _number=5, _variable=6;

struct node
{ int kind;
  int value;
  string name;
  vector <node *> sub;

  node(int k, int v=0, string n="")
  { kind=k;
    value=v;
    name=n; }
};

void print(node *n)
{ if (n==NULL)
    cout << "NULL!!!";
  else if (n->kind == _number)
    cout << n->value;
  else if (n->kind == _variable)
    cout << n->name;
  else if (n->kind == _binop)
  { if (n->sub.size() != 2)
      cout << "ERROR IN +!!!";
    else
    { cout << "(";
      print(n->sub[0]);
      cout << n->name;
      print(n->sub[1]);
      cout << ")"; } }
  else
    cout << "ERROR BAD KIND"; }

void main()
{ // 2*a+4/5/6
  node * two = new node(_number, 2);
  node * a = new node(_variable, 0, "a");
  node * left = new node(_binop, 0, "*");
  left->sub.push_back(two);
  left->sub.push_back(a);
  node * four = new node(_number, 4);
  node * five = new node(_number, 5);
  node * leftdiv = new node(_binop, 0, "/");
  leftdiv->sub.push_back(four);
  leftdiv->sub.push_back(five);
  node * six = new node(_number, 6);
  node * rightdiv = new node(_binop, 0, "/");
  rightdiv->sub.push_back(leftdiv);
  rightdiv->sub.push_back(six);
  node * root = new node(_binop, 0, "+");
  root->sub.push_back(left);
  root->sub.push_back(rightdiv);
  print(root);
  cout << "\n"; }