Given a string S, find out the length of the longest repeating substring(s). Return 0 if no repeating substring exists. Example 1: Input: S = "abcd" Output: 0 Explanation: There is no repeating substring. Example 2: Input: S = "abbaba" Output: 2 Explanation: The longest repeating substrings are "ab" and "ba", each of which occurs twice. Example 3: Input: S = "aabcaabdaab" Output: 3 Explanation: The longest repeating substring is "aab", which occurs 3 times. Example 4: Input: S = "aaaaa" Output: 4 Explanation: The longest repeating substring is "aaaa", which occurs twice. Constraints: The string S consists of only lowercase English letters from 'a' - 'z'. 1 <= S.length <= 1500