System.err.println(sexp);
  public static Sexp ibmToPenn(Sexp sexp) {    System.err.println(sexp);    if (sexp.isSymbol()) {      String str = sexp.toString();      Matcher m = underline.matcher(str);      if (m.matches()) {	SexpList list = new SexpList(2);	list.add(Symbol.get(m.group(1)));	list.add(Symbol.get(m.group(2)));	return list;      }    }    else {      SexpList treeList = sexp.list();      // in case extra info on final, redundant label, assign it to primary      // label slot      treeList.set(0, treeList.last());      treeList.remove(treeList.length() - 1);      int treeLen = treeList.length();      for (int i = 0; i < treeLen; ++i) {	treeList.set(i, ibmToPenn(treeList.get(i)));      }    }    return sexp;  }