modint = 998244353
n = int(input())
a = input()

to_z = [0]*n
to_o = [0]*n

flag_z = False
flag_o = False

for i in range(n):
	if a[i] == "1":
		to_z[i] = to_z[i-1] + 1
	else:
		to_z[i] = 0

for i in range(n):
	if a[-1-i] == "0":
		to_o[-1-i] = to_o[-i] + 1
	else:
		to_o[-1-i] = 0

ans = 1
flag = True
z, o = 0, 0
i = 0
while i < n and a[i] == "1":
	i+=1

while i < n:

	o = to_o[i]
	flag = False
	i += o

	if i == n:
		break

	while i < n and a[i] == "1":
		i += 1
	z = to_z[i-1]

	ans = (ans + ans * (z + o) ) % modint

print(ans % modint)