use std::io::*;

fn main() {
    let mut s: String = String::new();
    std::io::stdin().read_to_string(&mut s).ok();
    let mut itr = s.trim().split_whitespace();
    let n: usize = itr.next().unwrap().parse().unwrap();
    let s: Vec<char> = itr.next().unwrap().chars().collect();
    let mut a: Vec<i64> = (0..n)
        .map(|_| itr.next().unwrap().parse().unwrap())
        .collect();
    let mut ans = 0;
    for i in 0..n {
        if s[i] == 'B' {
            a[i] *= -1;
        }
    }
    let mut b = a.clone();
    for i in 0..n {
        b[i] *= -1;
    }

    let mut now = 0;
    for i in 0..n {
        now = std::cmp::max(a[i], a[i] + now);
        ans = std::cmp::max(ans, now);
    }
    now = 0;
    for i in 0..n {
        now = std::cmp::max(b[i], b[i] + now);
        ans = std::cmp::max(ans, now);
    }
    println!("{}", ans);
}