CF1450A.Avoid Trygub

A string $b$ is a subsequence of a string $a$ if $b$ can be obtained from $a$ by deletion of several (possibly, zero or all) characters. For example, "xy" is a subsequence of "xzyw" and "xy", but not "yx".

You are given a string $a$. Your task is to reorder the characters of $a$ so that "trygub" is not a subsequence of the resulting string.

In other words, you should find a string $b$ which is a permutation of symbols of the string $a$ and "trygub" is not a subsequence of $b$.

We have a truly marvelous proof that any string can be arranged not to contain "trygub" as a subsequence, but this problem statement is too short to contain it.

字符串 $b$ 是字符串 $a$ 的一个子序列，当且仅当 $b$ 可通过从 $a$ 中删除若干（可能为零个或全部）字符得到。例如，“xy” 是 “xzyw” 和 “xy” 的子序列，但不是 “yx” 的子序列。

给定一个字符串 $a$。你的任务是重排 $a$ 的字符，使得 “trygub” 不是所得字符串的子序列。

换言之，你需要找到一个字符串 $b$，它是字符串 $a$ 中所有字符的一个排列，且 “trygub” 不是 $b$ 的子序列。

我们有一个真正绝妙的证明：任意字符串均可被重排，使其不包含 “trygub” 作为子序列；但本题题干太短，无法容纳该证明。

The first line contains a single integer $t$ ($1\le t\le 100$) — the number of test cases.

The first line of each test case contains a single integer $n$ ($1\le n\le 200$) — the length of $a$.

The next line contains the string $a$ of length $n$, consisting of lowercase English letters.

第一行包含一个整数 $t$（$1\le t\le 100$）——测试用例的数量。

每个测试用例的第一行包含一个整数 $n$（$1\le n\le 200$）——字符串 $a$ 的长度。

接下来的一行包含一个长度为 $n$ 的字符串 $a$，由小写英文字母组成。

For each test case, output a string $b$ of length $n$ which is a permutation of characters of the string $a$, and such that "trygub" is not a subsequence of it.

If there exist multiple possible strings $b$, you can print any.

对于每个测试用例，输出一个长度为 $n$ 的字符串 $b$，使得 $b$ 是字符串 $a$ 中字符的一个排列，且 "trygub" 不是 $b$ 的子序列。

如果存在多个可能的字符串 $b$，你可以输出其中任意一个。

In the first test case, "bugyrtnotna" does not contain "trygub" as a subsequence. It does contain the letters of "trygub", but not in the correct order, so it is not a subsequence.

In the second test case, we did not change the order of characters because it is not needed.

In the third test case, "bruhtrywatchinggura" does contain "trygu" as a subsequence, but not "trygub".

在第一个测试用例中，“bugyrtnotna”不包含“trygub”作为子序列。它确实包含了“trygub”的所有字母，但顺序不正确，因此不是子序列。

在第二个测试用例中，我们未更改字符的顺序，因为这并非必要。

在第三个测试用例中，“bruhtrywatchinggura”包含“trygu”作为子序列，但不包含“trygub”。