Given a string s, return the last substring of s in lexicographical order.

Example 1:

Input: s = "abab"
Output: "bab"
Explanation: The substrings are ["a", "ab", "aba", "abab", "b", "ba", "bab"]. The lexicographically maximum substring is "bab".

Example 2:

Input: s = "leetcode"
Output: "tcode"

Constraints:

• 1 <= s.length <= 4 * 105
• s contains only lowercase English letters.