import java.io.*;
import java.util.*;
import java.util.function.*;
import java.util.stream.*;

public class Main {
    static final int MOD = 998244353;
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        List<Integer> ones = new ArrayList<>();
        char[] inputs = sc.next().toCharArray();
        for (int i = 0; i < n; i++) {
            if (inputs[i] == '1') {
                ones.add(i);
            }
        }
        if (ones.size() == 0) {
            System.out.println(0);
            return;
        }
        long base = 1;
        for (int i = 0; i < ones.size() - 1; i++) {
            base *= ones.get(i + 1) - ones.get(i) + 1;
            base %= MOD;
        }
        System.out.println(base);
    }
}
class Scanner {
    BufferedReader br;
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() {
        try {
            br = new BufferedReader(new InputStreamReader(System.in));
        } catch (Exception e) {
            
        }
    }
    
    public int nextInt() {
        return Integer.parseInt(next());
    }
    
    public long nextLong() {
        return Long.parseLong(next());
    }
    
    public double nextDouble() {
        return Double.parseDouble(next());
    }
    
    public String next() {
        try {
            while (!st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            return st.nextToken();
        }
    }
    
}