<p>Given a string <code>s</code> containing an out-of-order English representation of digits <code>0-9</code>, return <em>the digits in <strong>ascending</strong> order</em>.</p> <p> </p> <p><strong>Example 1:</strong></p> <pre><strong>Input:</strong> s = "owoztneoer" <strong>Output:</strong> "012" </pre><p><strong>Example 2:</strong></p> <pre><strong>Input:</strong> s = "fviefuro" <strong>Output:</strong> "45" </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= s.length <= 10<sup>5</sup></code></li> <li><code>s[i]</code> is one of the characters <code>["e","g","f","i","h","o","n","s","r","u","t","w","v","x","z"]</code>.</li> <li><code>s</code> is <strong>guaranteed</strong> to be valid.</li> </ul>