<p>Given a string <code>s</code> consisting of <strong>only</strong> the characters <code>'a'</code> and <code>'b'</code>, return <code>true</code> <em>if <strong>every</strong> </em><code>'a'</code> <em>appears before <strong>every</strong> </em><code>'b'</code><em> in the string</em>. Otherwise, return <code>false</code>.</p> <p> </p> <p><strong class="example">Example 1:</strong></p> <pre> <strong>Input:</strong> s = "aaabbb" <strong>Output:</strong> true <strong>Explanation:</strong> The 'a's are at indices 0, 1, and 2, while the 'b's are at indices 3, 4, and 5. Hence, every 'a' appears before every 'b' and we return true. </pre> <p><strong class="example">Example 2:</strong></p> <pre> <strong>Input:</strong> s = "abab" <strong>Output:</strong> false <strong>Explanation:</strong> There is an 'a' at index 2 and a 'b' at index 1. Hence, not every 'a' appears before every 'b' and we return false. </pre> <p><strong class="example">Example 3:</strong></p> <pre> <strong>Input:</strong> s = "bbb" <strong>Output:</strong> true <strong>Explanation:</strong> There are no 'a's, hence, every 'a' appears before every 'b' and we return true. </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= s.length <= 100</code></li> <li><code>s[i]</code> is either <code>'a'</code> or <code>'b'</code>.</li> </ul>