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

using namespace std;

struct node
{ string data;
  node * left, * right;

  node(string s)
  { data = s;
    left = NULL;
    right = NULL; }

  void enumerate(vector<string> & v)
  { if (this == NULL)
      return;
    left->enumerate(v);
    v.push_back(data);
    right->enumerate(v); }

};


class tree
{ protected:
    node * root;

  public:
    tree()
    { root = NULL; }

    void insert(string x)
    { if (root == NULL)
      { root = new node(x);
        return; }
      node * ptr = root, * prev = NULL;
      while (true)
      { if (x < ptr->data)
        { prev = ptr;
          ptr = ptr->left;
          if (ptr == NULL)
          { prev->left = new node(x);
            break; } }
        else
        { prev = ptr;
          ptr = ptr->right; 
          if (ptr == NULL)
          { prev->right = new node(x);
            break; } } } }

    void enumerate(vector<string> & v)
    { root->enumerate(v); }
};

int random_in_range(int a, int b)
{ return a + random() % (b - a + 1); }

string randomstring()
{ int len = random_in_range(3, 7);
  string s = "";
  for (int i = 0; i < len; i += 1)
    s += (char)random_in_range('A', 'Z');
  return s; }

void something(vector<string> & v)
{ tree T;
  for (int i = 0; i < v.size(); i += 1)
    T.insert(v[i]);
  v.clear();
  T.enumerate(v); }

int main(int argc, char * argv[])
{ srandomdev();
  if (argc != 2)
  { cerr << "Give me a number!\n";
    exit(1); }

  int N = atoi(argv[1]);
  vector<string> v;
  for (int i = 0; i < N; i += 1)
  { string s = randomstring();
    v.push_back(s); }
  
  something(v);

  for (int i = 0; i < N; i += 1)
    cout << v[i] << " "; }