def rle(s):
	n = len(s)
	i = 0
	r = []
	while i < n:
		j = i
		while j < n and s[j] == s[i]:
			j += 1
		r.append((s[i], j - i))
		i = j
	return r
n = int(input())
s = input().strip('0')
n = len(s)
ans = 1
for i, j in rle(s):
	if i == '0':
		ans = (ans * (j + 2)) % 998244353
	else:
		ans = ans * pow(2, j - 1, 998244353) % 998244353
print(ans)