<p>Given a string <code>s</code>. In one step you can insert any character at any index of the string.</p> <p>Return <em>the minimum number of steps</em> to make <code>s</code> palindrome.</p> <p>A <b>Palindrome String</b> is one that reads the same backward as well as forward.</p> <p> </p> <p><strong>Example 1:</strong></p> <pre> <strong>Input:</strong> s = "zzazz" <strong>Output:</strong> 0 <strong>Explanation:</strong> The string "zzazz" is already palindrome we don't need any insertions. </pre> <p><strong>Example 2:</strong></p> <pre> <strong>Input:</strong> s = "mbadm" <strong>Output:</strong> 2 <strong>Explanation:</strong> String can be "mbdadbm" or "mdbabdm". </pre> <p><strong>Example 3:</strong></p> <pre> <strong>Input:</strong> s = "leetcode" <strong>Output:</strong> 5 <strong>Explanation:</strong> Inserting 5 characters the string becomes "leetcodocteel". </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= s.length <= 500</code></li> <li><code>s</code> consists of lowercase English letters.</li> </ul>