AT_abc479_b.Longest Rainy Streak

Takahashi recorded the weather for $N$ consecutive days, recording each day as "sunny" or "rainy".
His record is given as a string $S$ of length $N$ in the following format.

• The $i$-th character ( $1 \le i \le N$ ) of $S$ represents the weather on the $i$-th day from the start of the record.
  • If the $i$-th character of $S$ is S, the record for that day was "sunny".
  • If the $i$-th character of $S$ is R, the record for that day was "rainy".

Find the maximum number of consecutive days for which Takahashi recorded "rainy".
If Takahashi never recorded "rainy", the answer is $0$.

高桥记录了连续 $N$ 天的天气，每天记录为“晴天”或“雨天”。
该记录以长度为 $N$ 的字符串 $S$ 给出，格式如下：

• 字符串 $S$ 的第 $i$ 个字符（$1 \le i \le N$）表示从记录开始起第 $i$ 天的天气。
  • 若 $S$ 的第 $i$ 个字符为 S，则当天记录为“晴天”；
  • 若 $S$ 的第 $i$ 个字符为 R，则当天记录为“雨天”。

求高桥记录中“雨天”连续出现的最大天数。
若高桥从未记录过“雨天”，则答案为 $0$。

The input is given from Standard Input in the following format:

$N$
$S$

输入从标准输入中按以下格式给出：

$N$
$S$

Output the answer.

输出答案。

Sample 1 Explanation:
Starting from the first day, Takahashi recorded rainy, rainy, sunny, rainy, rainy, rainy, sunny.
"Rainy" was recorded consecutively on days $4,5,6$, and there is no longer consecutive run of "rainy", so the maximum number of consecutive days with "rainy" recorded is $3$.

Sample 2 Explanation:
Takahashi never recorded "rainy". In this case, the answer is $0$.

Constraints

• $N$ is an integer satisfying $1 \le N \le 100$.
• $S$ is a string of length $N$ consisting of S and R.

样例 1 解释：
从第一天开始，高桥记录的天气依次为：雨、雨、晴、雨、雨、雨、晴。
其中，“雨”在第 $4,5,6$ 天连续出现，且不存在更长的连续“雨”记录，因此连续“雨”天数的最大值为 $3$。

样例 2 解释：
高桥从未记录过“雨”。此时答案为 $0$。

约束条件

• $N$ 是满足 $1 \le N \le 100$ 的整数。
• $S$ 是一个长度为 $N$ 的字符串，仅由字符 S 和 R 组成。