<p>You are given two positive integers <code>low</code> and <code>high</code>.</p> <p>An integer <code>x</code> consisting of <code>2 * n</code> digits is <strong>symmetric</strong> if the sum of the first <code>n</code> digits of <code>x</code> is equal to the sum of the last <code>n</code> digits of <code>x</code>. Numbers with an odd number of digits are never symmetric.</p> <p>Return <em>the <strong>number of symmetric</strong> integers in the range</em> <code>[low, high]</code>.</p> <p> </p> <p><strong class="example">Example 1:</strong></p> <pre> <strong>Input:</strong> low = 1, high = 100 <strong>Output:</strong> 9 <strong>Explanation:</strong> There are 9 symmetric integers between 1 and 100: 11, 22, 33, 44, 55, 66, 77, 88, and 99. </pre> <p><strong class="example">Example 2:</strong></p> <pre> <strong>Input:</strong> low = 1200, high = 1230 <strong>Output:</strong> 4 <strong>Explanation:</strong> There are 4 symmetric integers between 1200 and 1230: 1203, 1212, 1221, and 1230. </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= low <= high <= 10<sup>4</sup></code></li> </ul>