private boolean check() {
        if (!isBST())
            StdOut.println("Not in symmetric order");
        if (!isSizeConsistent())
            StdOut.println("Subtree counts not consistent");
        if (!isRankConsistent())
            StdOut.println("Ranks not consistent");
        if (!is23())
            StdOut.println("Not a 2-3 tree");
        if (!isBalanced())
            StdOut.println("Not balanced");
        return isBST() && isSizeConsistent() && isRankConsistent() && is23()
                && isBalanced();
    }