use std::io::*;
use std::str::FromStr;

fn main() {
    exec(read());
}

fn exec(i: String) {
    if i.is_empty() {
        return println!("{}", 1);
    }
    let char_list: Vec<char> = i.chars().collect();
    let length = char_list.len();
    let leftmost = multiple(length);
    let index = get_index(char_list);
    println!("{}", leftmost + index - 1);
}

fn multiple(i: usize) -> i64 {
    rec_power2(i, 1)
}

fn rec_power2(i: usize, acc: i64) -> i64 {
    if i == 0 {
        return acc;
    } else {
        rec_power2(i - 1, acc * 2)
    }
}

fn get_index(mut l: Vec<char>) -> i64 {
    let head = l.remove(0);
    if head == 'L' {
        rec_get_index(l, 1)
    } else {
        rec_get_index(l, 2)
    }
}

fn rec_get_index(mut l: Vec<char>, acc: i64) -> i64 {
    if l.is_empty() {
        return acc;
    }

    let head = l.remove(0);
    if head == 'L' {
        return rec_get_index(l, (acc * 2) - 1);
    } else {
        return rec_get_index(l, acc * 2);
    }
}

fn read<T: FromStr>() -> T {
    let mut s = String::new();
    stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}