Description

Each row in the cinema has $N$ seats. Seats are divided into regular seats ($\texttt S$) and couple seats ($\texttt L$). Couple seats always appear in pairs.

There is a cup holder between every two adjacent seats in the row (except between the two couple seats). In particular, there is also a cup holder at both ends of the row.

Now there are $N$ customers filling all $N$ seats. Find the maximum number of people who can use a cup holder.

Input Format

The first line contains an integer $N$.

The second line contains $N$ characters $\texttt{S/L}$, representing regular seats and couple seats.

Output Format

Output the maximum number of people who can use a cup holder.

3
SSS

3

4
SLLS

4

9
SLLLLSSLL

7

Hint

[Sample 3 Explanation]

If we use $\texttt *$ to represent cup holders, then the seats are as follows:

$\texttt{* S * L L * L L * S * S * L L *}$

[Constraints]

• For $100\%$ of the testdata, $1 \le N \le 50$.

[Hint and Notes]

This problem is translated from COCI 2011-2012 CONTEST #4 Task 1 KINO.

The score for this problem follows the original COCI settings, with a full score of $50$.

Translated by ChatGPT 5