import java.util.*;
import java.util.zip.*;
import java.util.List;
import java.util.regex.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import javax.swing.table.*;
import java.io.*;
import java.net.*;
import java.lang.reflect.*;
import java.lang.ref.*;
import java.lang.management.*;
import java.security.*;
import java.security.spec.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.imageio.*;
import java.math.*;
public class main {


static String alphabet = "abcdefghijklmnopqrstuvwxyz0123456789(),";

public static void main(String[] args) throws Exception {
  for (String s : allWordsOfAlphabet(alphabet))
    print(s);
}

static Iterable<String> allWordsOfAlphabet(final String alphabet) {
  return new IterableIterator<String>() {
    List<Integer> l = new ArrayList<Integer>();
    
    public boolean hasNext() {
      return true; // haha!
    }
    
    public String next() {
      String s = makeString();
      int i = 0;
      while (i < l(l)) {
        int n = l.get(i);
        if (n+1 < l(alphabet)) {
          l.set(i, n+1);
          break;
        }
        l.set(i++, 0);
      }
      if (i >= l(l)) l.add(0);
      return s;
    }
    
    String makeString() {
      StringBuilder buf = new StringBuilder(l(l));
      for (int i = 0; i < l(l); i++)
        buf.append(alphabet.charAt(l.get(i)));
      return str(buf);
    }
  };
}
static volatile StringBuffer local_log = new StringBuffer(); // not redirected
static volatile StringBuffer print_log = local_log; // might be redirected, e.g. to main bot

// in bytes - will cut to half that
static volatile int print_log_max = 1024*1024;
static volatile int local_log_max = 100*1024;
//static int print_maxLineLength = 0; // 0 = unset

static boolean print_silent; // total mute if set

static void print() {
  print("");
}

// slightly overblown signature to return original object...
static <A> A print(A o) {
  if (print_silent) return o;
  String s = String.valueOf(o) + "\n";
  // TODO if (print_maxLineLength != 0)
  StringBuffer loc = local_log;
  StringBuffer buf = print_log;
  int loc_max = print_log_max;
  if (buf != loc && buf != null) {
    print_append(buf, s, print_log_max);
    loc_max = local_log_max;
  }
  if (loc != null) 
    print_append(loc, s, loc_max);
  System.out.print(s);
  return o;
}

static void print(long l) {
  print(String.valueOf(l));
}

static void print(char c) {
  print(String.valueOf(c));
}

static void print_append(StringBuffer buf, String s, int max) {
  synchronized(buf) {
    buf.append(s);
    max /= 2;
    if (buf.length() > max) try {
      int newLength = max/2;
      int ofs = buf.length()-newLength;
      String newString = buf.substring(ofs);
      buf.setLength(0);
      buf.append("[...] ").append(newString);
    } catch (Exception e) {
      buf.setLength(0);
    }
  }
}


static String str(Object o) {
  return String.valueOf(o);
}
static int l(Object[] a) { return a == null ? 0 : a.length; }
static int l(byte[] a) { return a == null ? 0 : a.length; }
static int l(int[] a) { return a == null ? 0 : a.length; }
static int l(float[] a) { return a == null ? 0 : a.length; }
static int l(char[] a) { return a == null ? 0 : a.length; }
static int l(Collection c) { return c == null ? 0 : c.size(); }
static int l(Map m) { return m == null ? 0 : m.size(); }
static int l(String s) { return s == null ? 0 : s.length(); } 

static int l(Object o) {
  return l((List) o); // incomplete
}



// you still need to implement hasNext() and next()
static abstract class IterableIterator<A> implements Iterator<A>, Iterable<A> {
  public Iterator<A> iterator() {
    return this;
  }
  
  public void remove() {
    unsupportedOperation();
  }
}

static UnsupportedOperationException unsupportedOperation() {
  throw new UnsupportedOperationException();
}

}