this.prefix = prefix;
            this.children = children;
        }

        Node plus(String path) {
            return plusWithCommonPrefixLength(path, sizeOfCommonPrefix(path, 0));
        }

        private Node plusWithCommonPrefixLength(String path, int prefixLen) {
            int maxPos = Math.min(prefix.length(), path.length());
            if (prefixLen == maxPos) {