const MOD: usize = 998244353;

fn power(base: usize, times: usize) -> usize {
    if times == 0 { return 1usize; }
    if times == 1 { return base; }
    let temp = power(base, times/2);
    temp * temp % MOD * power(base, times%2) % MOD
}

fn comb(n: usize, r: usize) -> usize {
    let mut ret = 1usize;
    for i in 1..=r {
        ret *= n+1-i;
        ret %= MOD;
        ret *= power(i, MOD-2);
        ret %= MOD;
    }
    ret
}

fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let s = s.trim().chars().collect::<Vec<char>>();

    let cds = s.iter().filter(|&&c| c == 'C' || c == 'D').count();
    if cds == 0 || cds == n {
        println!("1");
        return;
    }
    println!("{}", comb(n+1-cds-1 + cds, cds));
}