using System.Collections;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

internal class Program
{
    private const long mod = 998244353;

    
    public static void Main(string[] args)
    {
        long ans = 1;
        int n = int.Parse(Console.ReadLine());
        string s = Console.ReadLine();
        int le = 0;

        void upd(int c)
        {
            ans = ans * (c + 2) % mod;
        }

        for (int i = 0; i < s.Length; i++)
        {
            if (s[i] == '1')
            {
                if (le > 0) upd(i - le);
                le = i + 1;
            }
        }

        if (le == 0) ans = 0;
        Console.WriteLine(ans);
    }

    public static List<int> mkar(int n, int val)
    {
        List<int> res = new List<int>(n);
        for(int i=0;i<n;i++)res.Add(val);
        return res;
    }
}