<p>There is an undirected <strong>star</strong> graph consisting of <code>n</code> nodes labeled from <code>1</code> to <code>n</code>. A star graph is a graph where there is one <strong>center</strong> node and <strong>exactly</strong> <code>n - 1</code> edges that connect the center node with every other node.</p> <p>You are given a 2D integer array <code>edges</code> where each <code>edges[i] = [u<sub>i</sub>, v<sub>i</sub>]</code> indicates that there is an edge between the nodes <code>u<sub>i</sub></code> and <code>v<sub>i</sub></code>. Return the center of the given star graph.</p> <p> </p> <p><strong>Example 1:</strong></p> <img alt="" src="https://assets.leetcode.com/uploads/2021/02/24/star_graph.png" style="width: 331px; height: 321px;" /> <pre> <strong>Input:</strong> edges = [[1,2],[2,3],[4,2]] <strong>Output:</strong> 2 <strong>Explanation:</strong> As shown in the figure above, node 2 is connected to every other node, so 2 is the center. </pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> edges = [[1,2],[5,1],[1,3],[1,4]] <strong>Output:</strong> 1 </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>3 <= n <= 10<sup>5</sup></code></li> <li><code>edges.length == n - 1</code></li> <li><code>edges[i].length == 2</code></li> <li><code>1 <= u<sub>i,</sub> v<sub>i</sub> <= n</code></li> <li><code>u<sub>i</sub> != v<sub>i</sub></code></li> <li>The given <code>edges</code> represent a valid star graph.</li> </ul>