Find the Maximum Length of Repeated Characters in K Changes

You are given a string `s` of lowercase letters and an integer `k`. You can change up to `k` characters in the string to make all characters in a substring the same. Your task is to find the length of the longest substring that can be obtained after performing at most `k` changes. Input: - A single line containing the string `s`. - A single integer `k`. Output: - An integer representing the maximum length of the substring after `k` changes. Example: Input: abaa 1 Output: 4 In this example, we can change one 'b' to 'a' to form 'aaaa', resulting in a length of 4.