Tim is doing a test consisting of (4n) questions; each question has (4) options: ' A ', ' B ', ' C ', and ' D '. For each option, there are exactly (n) correct answers corresponding to that option — meaning there are (n) questions with the answer ' A ', (n) questions with the answer ' B ', (n) questions with the answer ' C ', and (n) questions with the answer ' D '. For each question, Tim wrote his answer on the answer sheet. If he could not figure out the answer, he would leave a question mark ' ? ' for that question. You are given his answer sheet of (4n) characters. What is the maximum number of correct answers Tim can get? The first line contains a single integer (t) ((1 \le t \le 1000)) — the number of test cases. The first line of each test case contains an integer (n) ((1 \le n \le 100)). The second line of each test case contains a string (s) of (4n) characters ((s_i \in \{A, B, C, D, ?\})) — Tim's answers for the questions. For each test case, print a single integer — the maximum score that Tim can achieve. In the first test case, there is exactly one question with each answer ' A ', ' B ', ' C ', and ' D '; so it's possible that Tim gets all his answers correct. In the second test case, there are only two correct answers ' A ' which makes him get exactly (2) points in any case. In the third test case, Tim can get at most (2) correct answers with option ' A ' and (2) correct answers with option ' B '. For example, he would get (4) points if the answers were ' AACCBBDD '. In the fourth test case, he refuses to answer any question at all, which makes him get (0) points.