CF1796A.Typical Interview Problem

The FB-string is formed as follows. Initially, it is empty. We go through all positive integers, starting from $1$, in ascending order, and do the following for each integer:

• if the current integer is divisible by $3$, append F to the end of the FB-string;
• if the current integer is divisible by $5$, append B to the end of the FB-string.

Note that if an integer is divisible by both $3$ and $5$, we append F, and then B, not in the opposite order.

The first $10$ characters of the FB-string are FBFFBFFBFB: the first F comes from the integer $3$, the next character (B) comes from $5$, the next F comes from the integer $6$, and so on. It's easy to see that this string is infinitely long. Let $f_i$ be the $i$-th character of FB-string; so, $f_1$ is F, $f_2$ is B, $f_3$ is F, $f_4$ is F, and so on.

You are given a string $s$, consisting of characters F and/or B. You have to determine whether it is a substring (contiguous subsequence) of the FB-string. In other words, determine if it is possible to choose two integers $l$ and $r$ ($1 \le l \le r$) so that the string $f_l f_{l+1} f_{l+2} \dots f_r$ is exactly $s$.

For example:

• FFB is a substring of the FB-string: if we pick $l = 3$ and $r = 5$, the string $f_3 f_4 f_5$ is exactly FFB;
• BFFBFFBF is a substring of the FB-string: if we pick $l = 2$ and $r = 9$, the string $f_2 f_3 f_4 \dots f_9$ is exactly BFFBFFBF;
• BBB is not a substring of the FB-string.

FB字符串按如下方式构造：初始时为空。我们从 $1$ 开始，依次遍历所有正整数（升序），对每个整数执行以下操作：

• 若当前整数能被 $3$ 整除，则在 FB 字符串末尾添加字符 F；
• 若当前整数能被 $5$ 整除，则在 FB 字符串末尾添加字符 B。

注意：若某个整数同时能被 $3$ 和 $5$ 整除（即能被 $15$ 整除），则先添加 F，再添加 B，顺序不可颠倒。

FB 字符串的前 $10$ 个字符为 FBFFBFFBFB：第一个 F 来自整数 $3$，下一个字符（B）来自 $5$，再下一个 F 来自整数 $6$，依此类推。显然，该字符串是无限长的。记 $f_i$ 为 FB 字符串的第 $i$ 个字符；因此，$f_1 = \text{F}$，$f_2 = \text{B}$，$f_3 = \text{F}$，$f_4 = \text{F}$，等等。

给定一个仅由字符 F 和/或 B 组成的字符串 $s$，你需要判断它是否为 FB 字符串的一个子串（即连续子序列）。换言之，需判断是否存在两个整数 $l$ 和 $r$（满足 $1 \le l \le r$），使得字符串 $f_l f_{l+1} f_{l+2} \dots f_r$ 恰好等于 $s$。

例如：

• FFB 是 FB 字符串的一个子串：取 $l = 3$、$r = 5$，则 $f_3 f_4 f_5$ 恰好为 FFB；
• BFFBFFBF 是 FB 字符串的一个子串：取 $l = 2$、$r = 9$，则 $f_2 f_3 f_4 \dots f_9$ 恰好为 BFFBFFBF；
• BBB 不是 FB 字符串的子串。

The first line contains one integer $t$ ($1 \le t \le 2046$) — the number of test cases.

Each test case consists of two lines. The first line contains one integer $k$ ($1 \le k \le 10$) — the number of characters in $s$. The second line contains $s$, which is a string of exactly $k$ characters. Each character of $s$ is either F or B.

第一行包含一个整数 $t$（$1 \le t \le 2046$）—— 测试用例的数量。

每个测试用例由两行组成。第一行包含一个整数 $k$（$1 \le k \le 10$）—— 字符串 $s$ 的字符个数。第二行包含字符串 $s$，其长度恰好为 $k$。$s$ 的每个字符均为 F 或 B。

For each test case, print YES if $s$ is a substring of the FB-string, or NO otherwise.

You may print each letter in any case (YES, yes, Yes will all be recognized as positive answer, NO, no and nO will all be recognized as negative answer).

对于每个测试用例，如果 $s$ 是 FB-字符串的子串，则输出 YES；否则输出 NO。

你可以以任意大小写形式输出每个字母（例如 YES、yes、Yes 均被视为肯定回答，NO、no、nO 均被视为否定回答）。