Damaged XML

XML is a widely used format for data exchange between different software applications. Recently, a programmer named Oleksii developed a small program that stores important information as an XML string.

An XML string is composed of opening and closing tags. An opening tag begins with a left angle bracket ($<$), followed by a tag name, which is a non-empty string of lowercase Latin letters, and ends with a right angle bracket ($>$). Examples of opening tags include: <a>, <dog>.

A closing tag starts with a left angle bracket, followed by a forward slash (/), the tag name (a non-empty string of lowercase Latin letters), and ends with a right angle bracket. Examples of closing tags are: </a>, </dog>.

An XML string is considered correct if it can be constructed using the following rules:

• An empty string is a correct XML string.

• If $A$ and $B$ are correct XML strings, then the concatenated string $AB$ is also a correct XML string.

• If $A$ is a correct XML string, then the string <X>A</X>, formed by enclosing $A$ with an opening tag and a matching closing tag, is also a correct XML string. Here, $X$ is any non-empty string of lowercase Latin letters.

For instance, the following strings:

<a></a> <a><ab></ab><c></c></a> <a></a><a></a><a></a>

are correct XML strings, whereas strings like:

<a></b> <a><b> <a><b></a></b>

are not correct XML strings.

Oleksii emailed a file containing the XML string to his colleague Petrov. Unfortunately, the file was corrupted during transmission: exactly one character in the string was altered.

Your task is to write a program that, given the string received by Petrov, restores the original XML string that Oleksii sent.