use std::io::{self, Read};

const MOD: u64 = 998244353;

fn main() {
    let mut s = String::new();
    io::stdin().read_to_string(&mut s).unwrap();
    let mut it = s.split_whitespace();
    let n: usize = it.next().unwrap().parse().unwrap();
    let a = it.next().unwrap().as_bytes().to_vec();

    let mut runs = Vec::<(u8, usize)>::new();
    let mut i = 0usize;
    while i < n {
        let mut j = i;
        while j < n && a[j] == a[i] {
            j += 1;
        }
        runs.push((a[i], j - i));
        i = j;
    }

    let mut ans = 1u64;
    for i in 0..runs.len().saturating_sub(1) {
        if runs[i].0 == b'0' && runs[i + 1].0 == b'1' {
            let x = (runs[i].1 + runs[i + 1].1 + 1) as u64;
            ans = ans * x % MOD;
        }
    }

    println!("{}", ans);
}