#![allow(dead_code, unused_imports, unused_macros, non_snake_case)]

fn main() {
  input! {
    N: usize,
    A: Chars,
  }

  let mut rle = vec![('_', 0)];
  for i in 0 .. N {
    let last = rle.last_mut().unwrap();
    if A[i] == last.0 {
      last.1 += 1;
    } else {
      rle.push((A[i], 1));
    }
  }

  rle.remove(0);
  if let Some(&('1', _)) = rle.first() {
    rle.remove(0);
  }
  if let Some(&('0', _)) = rle.last() {
    rle.pop();
  }
  
  let mut ans = 1;
  for i in 0 .. rle.len() / 2 {
    let a = rle[i * 2].1 as i64;
    let b = rle[i * 2 + 1].1 as i64;
    ans *= (a + b + 1) % MOD;
    ans = ans.rem_euclid(MOD);
  }
  println!("{ans}");
}

const MOD: i64 = 998244353;

use proconio::{input, input_interactive, marker::{Chars, Bytes, Usize1}};

fn mod_pow(mut a: i64, mut b: i64) -> i64 {
  let mut r = 1;
  while b > 0 {
    if b & 1 != 0 {
      r = r * a % MOD;
    }
    a = a * a % MOD;
    b >>= 1;
  }
  r
}