<p>There are <code>n</code> <strong>piles</strong> of coins on a table. Each pile consists of a <strong>positive number</strong> of coins of assorted denominations.</p> <p>In one move, you can choose any coin on <strong>top</strong> of any pile, remove it, and add it to your wallet.</p> <p>Given a list <code>piles</code>, where <code>piles[i]</code> is a list of integers denoting the composition of the <code>i<sup>th</sup></code> pile from <strong>top to bottom</strong>, and a positive integer <code>k</code>, return <em>the <strong>maximum total value</strong> of coins you can have in your wallet if you choose <strong>exactly</strong></em> <code>k</code> <em>coins optimally</em>.</p> <p> </p> <p><strong class="example">Example 1:</strong></p> <img alt="" src="https://assets.leetcode.com/uploads/2019/11/09/e1.png" style="width: 600px; height: 243px;" /> <pre> <strong>Input:</strong> piles = [[1,100,3],[7,8,9]], k = 2 <strong>Output:</strong> 101 <strong>Explanation:</strong> The above diagram shows the different ways we can choose k coins. The maximum total we can obtain is 101. </pre> <p><strong class="example">Example 2:</strong></p> <pre> <strong>Input:</strong> piles = [[100],[100],[100],[100],[100],[100],[1,1,1,1,1,1,700]], k = 7 <strong>Output:</strong> 706 <strong>Explanation: </strong>The maximum total can be obtained if we choose all coins from the last pile. </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>n == piles.length</code></li> <li><code>1 <= n <= 1000</code></li> <li><code>1 <= piles[i][j] <= 10<sup>5</sup></code></li> <li><code>1 <= k <= sum(piles[i].length) <= 2000</code></li> </ul>