package main

import . "fmt"

const M = 998244353

func main() {
	var n int
	var a string
	Scan(&n,&a)
	cur := -1
	zeros := 0
	ones := 0
	ans := 1
	for _, ch := range a {
		switch cur {
			case -1:
				if ch == '0' {
					cur = 0
					zeros = 1
					ones = 0
				}
			case 0:
				if ch == '0' {
					zeros++
				} else {
					cur = 1
					ones = 1
				}
			case 1:
				if ch == '0' {
					ans = ans * (1+zeros+ones) % M
					cur = 0
					zeros = 1
					ones = 0
				} else {
					ones++
				}
		}
	}
	if cur == 1 {
		ans = ans * (1+zeros+ones) % M
	}
	Println(ans)
}