CF2047B Replace Character

You're given a string $ s $ of length $ n $ , consisting of only lowercase English letters. You must do the following operation exactly once: - Choose any two indices $ i $ and $ j $ ( $ 1 \le i, j \le n $ ). You can choose $ i = j $ . - Set $ s_i := s_j $ . You need to minimize the number of distinct permutations $ ^\dagger $ of $ s $ . Output any string with the smallest number of distinct permutations after performing exactly one operation. $ ^\dagger $ A permutation of the string is an arrangement of its characters into any order. For example, "bac" is a permutation of "abc" but "bcc" is not.

Each test contains multiple test cases. The first line contains the number of test cases $ t $ ( $ 1 \le t \le 500 $ ). The description of the test cases follows. The first line of each test case contains $ n $ ( $ 1 \le n \le 10 $ ) — the length of string $ s $ . The second line of each test case contains $ s $ of length $ n $ . The string contains only lowercase English letters.

For each test case, output the required $ s $ after applying exactly one operation. If there are multiple solutions, print any of them.

In the first test case, we can obtain the following strings in one operation: "abc", "bbc", "cbc", "aac", "acc", "aba", and "abb". The string "abc" has $ 6 $ distinct permutations: "abc", "acb", "bac", "bca", "cab", and "cba". The string "cbc" has $ 3 $ distinct permutations: "bcc", "cbc", and "ccb", which is the lowest of all the obtainable strings. In fact, all obtainable strings except "abc" have $ 3 $ permutations, so any of them would be accepted.