<p>You are given an <code>n x n</code> integer <code>matrix</code>. You can do the following operation <strong>any</strong> number of times:</p> <ul> <li>Choose any two <strong>adjacent</strong> elements of <code>matrix</code> and <strong>multiply</strong> each of them by <code>-1</code>.</li> </ul> <p>Two elements are considered <strong>adjacent</strong> if and only if they share a <strong>border</strong>.</p> <p>Your goal is to <strong>maximize</strong> the summation of the matrix's elements. Return <em>the <strong>maximum</strong> sum of the matrix's elements using the operation mentioned above.</em></p> <p> </p> <p><strong>Example 1:</strong></p> <img alt="" src="https://assets.leetcode.com/uploads/2021/07/16/pc79-q2ex1.png" style="width: 401px; height: 81px;" /> <pre> <strong>Input:</strong> matrix = [[1,-1],[-1,1]] <strong>Output:</strong> 4 <b>Explanation:</b> We can follow the following steps to reach sum equals 4: - Multiply the 2 elements in the first row by -1. - Multiply the 2 elements in the first column by -1. </pre> <p><strong>Example 2:</strong></p> <img alt="" src="https://assets.leetcode.com/uploads/2021/07/16/pc79-q2ex2.png" style="width: 321px; height: 121px;" /> <pre> <strong>Input:</strong> matrix = [[1,2,3],[-1,-2,-3],[1,2,3]] <strong>Output:</strong> 16 <b>Explanation:</b> We can follow the following step to reach sum equals 16: - Multiply the 2 last elements in the second row by -1. </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>n == matrix.length == matrix[i].length</code></li> <li><code>2 <= n <= 250</code></li> <li><code>-10<sup>5</sup> <= matrix[i][j] <= 10<sup>5</sup></code></li> </ul>