static class LSystem {
  static char [] alphabet = {
    'F', 'X', 'Y', '+', '-', '[', ']'  };
  static String axiom;
  static String [] rule = {
    "F", "X", "Y", "+", "-", "[", "]"  };
  static String tree;
  LSystem(String axiom, String [] ruleset){
    for(int i = 0; i < ruleset.length; i++){
      rule[i] = ruleset[i];
    }
    this.axiom = axiom;
    tree = "";
  }
  void iterate(int maxLength){
    tree = new String(axiom);
    int [] ruleLength = new int[alphabet.length];
    for (int i = 0; i < alphabet.length; i++){
      ruleLength[i] = rule[i].length();
    }
    for (int i = 0; i < maxLength; i++){
      int newLength = 0;
      for (int j = 0; j < tree.length(); j++){
        char c = tree.charAt(j);
        for (int k = 0; k < alphabet.length; k++){
          if (c == alphabet[k]){
            newLength += ruleLength[k];
            break;
          }
        }
      }
      StringBuffer newTree = new StringBuffer(newLength);
      for (int j = 0; j < tree.length(); j++){
        char c = tree.charAt(j);
        for (int k = 0; k < alphabet.length; k++){
          if (c == alphabet[k]){
            newTree.append(rule[k]);
            break;
          }
        }
      }
      tree = newTree.toString();
    }
  }
}