Please subscribe to the official Codeforces channel in Telegram via the link: https://t.me/codeforces_official.
×

Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ACM-ICPC mode for virtual contests.
If you've seen these problems, a virtual contest is not for you - solve these problems in the archive.
If you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.
Never use someone else's code, read the tutorials or communicate with other person during a virtual contest.

No tag edit access

B. Domino Effect

time limit per test

1 secondmemory limit per test

256 megabytesinput

standard inputoutput

standard outputLittle Chris knows there's no fun in playing dominoes, he thinks it's too random and doesn't require skill. Instead, he decided to play with the dominoes and make a "domino show".

Chris arranges *n* dominoes in a line, placing each piece vertically upright. In the beginning, he simultaneously pushes some of the dominoes either to the left or to the right. However, somewhere between every two dominoes pushed in the same direction there is at least one domino pushed in the opposite direction.

After each second, each domino that is falling to the left pushes the adjacent domino on the left. Similarly, the dominoes falling to the right push their adjacent dominoes standing on the right. When a vertical domino has dominoes falling on it from both sides, it stays still due to the balance of the forces. The figure shows one possible example of the process.

Given the initial directions Chris has pushed the dominoes, find the number of the dominoes left standing vertically at the end of the process!

Input

The first line contains a single integer *n* (1 ≤ *n* ≤ 3000), the number of the dominoes in the line. The next line contains a character string *s* of length *n*. The *i*-th character of the string *s*_{i} is equal to

- "L", if the
*i*-th domino has been pushed to the left; - "R", if the
*i*-th domino has been pushed to the right; - ".", if the
*i*-th domino has not been pushed.

It is guaranteed that if *s*_{i} = *s*_{j} = "L" and *i* < *j*, then there exists such *k* that *i* < *k* < *j* and *s*_{k} = "R"; if *s*_{i} = *s*_{j} = "R" and *i* < *j*, then there exists such *k* that *i* < *k* < *j* and *s*_{k} = "L".

Output

Output a single integer, the number of the dominoes that remain vertical at the end of the process.

Examples

Input

14

.L.R...LR..L..

Output

4

Input

5

R....

Output

0

Input

1

.

Output

1

Note

The first example case is shown on the figure. The four pieces that remain standing vertically are highlighted with orange.

In the second example case, all pieces fall down since the first piece topples all the other pieces.

In the last example case, a single piece has not been pushed in either direction.

Codeforces (c) Copyright 2010-2018 Mike Mirzayanov

The only programming contests Web 2.0 platform

Server time: Dec/19/2018 13:41:53 (d1).

Desktop version, switch to mobile version.

Supported by

User lists

Name |
---|