<p>A string is considered <strong>beautiful</strong> if it satisfies the following conditions:</p> <ul> <li>Each of the 5 English vowels (<code>'a'</code>, <code>'e'</code>, <code>'i'</code>, <code>'o'</code>, <code>'u'</code>) must appear <strong>at least once</strong> in it.</li> <li>The letters must be sorted in <strong>alphabetical order</strong> (i.e. all <code>'a'</code>s before <code>'e'</code>s, all <code>'e'</code>s before <code>'i'</code>s, etc.).</li> </ul> <p>For example, strings <code>"aeiou"</code> and <code>"aaaaaaeiiiioou"</code> are considered <strong>beautiful</strong>, but <code>"uaeio"</code>, <code>"aeoiu"</code>, and <code>"aaaeeeooo"</code> are <strong>not beautiful</strong>.</p> <p>Given a string <code>word</code> consisting of English vowels, return <em>the <strong>length of the longest beautiful substring</strong> of </em><code>word</code><em>. If no such substring exists, return </em><code>0</code>.</p> <p>A <strong>substring</strong> is a contiguous sequence of characters in a string.</p> <p> </p> <p><strong>Example 1:</strong></p> <pre> <strong>Input:</strong> word = "aeiaaio<u>aaaaeiiiiouuu</u>ooaauuaeiu" <strong>Output:</strong> 13 <b>Explanation:</b> The longest beautiful substring in word is "aaaaeiiiiouuu" of length 13.</pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> word = "aeeeiiiioooauuu<u>aeiou</u>" <strong>Output:</strong> 5 <b>Explanation:</b> The longest beautiful substring in word is "aeiou" of length 5. </pre> <p><strong>Example 3:</strong></p> <pre> <strong>Input:</strong> word = "a" <strong>Output:</strong> 0 <b>Explanation:</b> There is no beautiful substring, so return 0. </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= word.length <= 5 * 10<sup>5</sup></code></li> <li><code>word</code> consists of characters <code>'a'</code>, <code>'e'</code>, <code>'i'</code>, <code>'o'</code>, and <code>'u'</code>.</li> </ul>