CF1632A.ABC

Recently, the students of School 179 have developed a unique algorithm, which takes in a binary string $s$ as input. However, they soon found out that if some substring $t$ of $s$ is a palindrome of length greater than 1, the algorithm will work incorrectly. Can the students somehow reorder the characters of $s$ so that the algorithm will work correctly on the string?

A binary string is a string where each character is either 0 or 1.

A string $a$ is a substring of a string $b$ if $a$ can be obtained from $b$ by deletion of several (possibly, zero or all) characters from the beginning and several (possibly, zero or all) characters from the end.

A palindrome is a string that reads the same backwards as forwards.

最近，179 号学校的学生们开发了一种独特的算法，该算法以一个二进制字符串 $s$ 作为输入。然而，他们很快发现：如果 $s$ 的某个子串 $t$ 是长度大于 1 的回文串，则该算法将无法正确运行。学生们能否通过重新排列 $s$ 中的字符，使得该算法在重排后的字符串上能正确运行？

二进制字符串是指每个字符均为 0 或 1 的字符串。

若字符串 $a$ 可通过对字符串 $b$ 删除其开头若干个（可能为零个或全部）字符以及结尾若干个（可能为零个或全部）字符而得到，则称 $a$ 是 $b$ 的一个子串。

回文串是指正读与反读都相同的字符串。

Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 100$). Description of the test cases follows.

The first line of each test case contains a single integer $n$ ($1 \le n \le 100$) — the length of the string $s$.

The second line of each test case contains the string $s$ of length $n$ consisting only of the characters 0 and 1.

每个测试包含多个测试用例。第一行包含测试用例的数量 $t$（$1 \le t \le 100$）。随后是测试用例的描述。

每个测试用例的第一行包含一个整数 $n$（$1 \le n \le 100$）—— 字符串 $s$ 的长度。

每个测试用例的第二行包含一个长度为 $n$ 的字符串 $s$，该字符串仅由字符 0 和 1 组成。

For each test case, print YES (case-insensitive) if it is possible to reorder the characters of $s$ so that there are no substrings that are a palindrome of length greater than 1, or NO (case-insensitive) otherwise.

对于每个测试用例，如果可以重新排列字符串 $s$ 的字符，使得其中不存在长度大于 1 的回文子串，则输出 YES（不区分大小写）；否则输出 NO（不区分大小写）。

In the first three test cases, the given strings do not contain palindromes of length greater than 1, so the answers are YES.

In the last test case, it is impossible to reorder the characters so that the string does not contain palindromes of length greater than 1, so the answer is NO.

在前三个测试用例中，给定的字符串不包含长度大于 1 的回文子串，因此答案为 YES。

在最后一个测试用例中，无法重新排列字符使得字符串不包含长度大于 1 的回文子串，因此答案为 NO。