Problem:
Score : 100 points

Problem Statement

We have weather records at AtCoder Town for some consecutive three days. A string of length 3, S, represents the records - if the i-th character is S, it means it was sunny on the i-th day; if that character is R, it means it was rainy on that day.

Find the maximum number of consecutive rainy days in this period.

Constraints

|S| = 3

Each character of S is S or R.

Input

Input is given from Standard Input in the following format:

S

Output

Print the maximum number of consecutive rainy days in the period.

Sample Input 1

RRS

Sample Output 1

2

We had rain on the 1-st and 2-nd days in the period. Here, the maximum number of consecutive rainy days is 2, so we should print 2.

Sample Input 2

SSS

Sample Output 2

0

It was sunny throughout the period. We had no rainy days, so we should print 0.

Sample Input 3

RSR

Sample Output 3

1

We had rain on the 1-st and 3-rd days - two "streaks" of one rainy day, so we should print 1.

Solution in Rust (1.42.0) (judge verdict: Accepted)

#![allow(unused_imports)]

use std::cmp::{max, min};
use std::collections::*;
use std::io::{stdin, stdout, BufWriter, Write};

#[derive(Default)]
struct Scanner {
    buffer: Vec<String>,
}
impl Scanner {
    fn next<T: std::str::FromStr>(&mut self) -> T {
        loop {
            if let Some(token) = self.buffer.pop() {
                return token.parse().ok().expect("Failed parse");
            }
            let mut input = String::new();
            stdin().read_line(&mut input).expect("Failed read");
            self.buffer = input.split_whitespace().rev().map(String::from).collect();
        }
    }
}

fn solve() {
    let mut scan = Scanner::default();
    let s: String = scan.next();
    let mut cont = 0;
    let mut res = 0;
    for c in s.chars() {
        if c == 'R' {
            cont += 1;
        } else {
            cont = 0;
        }
        res = max(res, cont);
    }
    println!( "{}", res);
}

fn main() {
    let mut scan = Scanner::default();
    // let t = scan.next::<u64>();
    let t = 1;
    for _ in 0..t {
        solve();
    }
}