<p>A valid parentheses string is either empty <code>""</code>, <code>"(" + A + ")"</code>, or <code>A + B</code>, where <code>A</code> and <code>B</code> are valid parentheses strings, and <code>+</code> represents string concatenation.</p> <ul> <li>For example, <code>""</code>, <code>"()"</code>, <code>"(())()"</code>, and <code>"(()(()))"</code> are all valid parentheses strings.</li> </ul> <p>A valid parentheses string <code>s</code> is primitive if it is nonempty, and there does not exist a way to split it into <code>s = A + B</code>, with <code>A</code> and <code>B</code> nonempty valid parentheses strings.</p> <p>Given a valid parentheses string <code>s</code>, consider its primitive decomposition: <code>s = P<sub>1</sub> + P<sub>2</sub> + ... + P<sub>k</sub></code>, where <code>P<sub>i</sub></code> are primitive valid parentheses strings.</p> <p>Return <code>s</code> <em>after removing the outermost parentheses of every primitive string in the primitive decomposition of </em><code>s</code>.</p> <p> </p> <p><strong class="example">Example 1:</strong></p> <pre> <strong>Input:</strong> s = "(()())(())" <strong>Output:</strong> "()()()" <strong>Explanation:</strong> The input string is "(()())(())", with primitive decomposition "(()())" + "(())". After removing outer parentheses of each part, this is "()()" + "()" = "()()()". </pre> <p><strong class="example">Example 2:</strong></p> <pre> <strong>Input:</strong> s = "(()())(())(()(()))" <strong>Output:</strong> "()()()()(())" <strong>Explanation:</strong> The input string is "(()())(())(()(()))", with primitive decomposition "(()())" + "(())" + "(()(()))". After removing outer parentheses of each part, this is "()()" + "()" + "()(())" = "()()()()(())". </pre> <p><strong class="example">Example 3:</strong></p> <pre> <strong>Input:</strong> s = "()()" <strong>Output:</strong> "" <strong>Explanation:</strong> The input string is "()()", with primitive decomposition "()" + "()". After removing outer parentheses of each part, this is "" + "" = "". </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= s.length <= 10<sup>5</sup></code></li> <li><code>s[i]</code> is either <code>'('</code> or <code>')'</code>.</li> <li><code>s</code> is a valid parentheses string.</li> </ul>