class Solution {
    public int characterReplacement(String s, int k) {
        return Math.max(helper(s, k), helper(new StringBuilder(s).reverse().toString(), k));
    }
    public int helper(String s, int k) {
        int max = -1;
        int counter = 0;
        int k2 = k;

        for(int i = 0; i<s.length(); i++) {
            char candidate = s.charAt(i);
            counter = 1;
            k2 = k;
            for(int j = i +1; j<s.length();j++) {
                if(candidate == s.charAt(j)) {
                    counter++;
                } else {
                    if(k2>0) {
                        k2--;
                        counter++;
                    } else {
                        break;
                    }
                }
            max = Math.max(counter, max);
            }
        }
        return max;
    }
}