#include <iostream>
#include <fstream>
#include <string>

struct treenode
{ int data;
  treenode * left, * right;

  treenode(int n, treenode * l = NULL, treenode * r = NULL)
  { data=n; left=l; right=r; }
};

void insert(treenode * & T, int N)
{ if (T==NULL)
    T = new treenode(N);
  else if (T->data==N)
    { }
  else if (N < T->data)
    insert(T->left, N);
  else
    insert(T->right, N); }

void print(treenode * T, ostream & fo)
{ if (T==NULL)
    fo << "@ ";
  else
  { fo << "( ";
    print(T->left, fo);
    fo << T->data << " ";
    print(T->right, fo);
    fo << ") "; } }

void print_differently(treenode * T, ostream & fo)
{ if (T==NULL)
    fo << "@ ";
  else
  { fo << "( ";
    fo << T->data << " ";
    print_differently(T->left, fo);
    print_differently(T->right, fo);
    fo << ") "; } }

treenode * read(istream & fi)
{ char c;
  fi >> c;
  if (c=='@')
    return NULL;
  else if (c=='(')
  { treenode * L = read(fi);
    int N;
    fi >> N;
    treenode * R = read(fi);
    char c;
    fi >> c;
    if (c!=')')
    { cerr << "saw " << c << " when expecting )\n";
      return NULL; }
    return new treenode(N, L, R); }
  else
  { cerr << "first char " << c << " not ( or @\n";
    return NULL; } }

treenode * read_old_way(istream & fin)
{ treenode * t = NULL;
  while (true)
  { int x;
    fin >> x;
    if (fin.fail())
      break;
    insert(t, x); }
  return t; }

void main()
{ treenode * collection = NULL;
  ifstream fin("output");
  collection = read(fin);
  fin.close();
  ofstream fout("output");
  print_differently(collection, cout);
  cout << "\n";
  fout.close(); }