# できることは  0を右に伸ばす  と  1を左に伸ばす
# 101 なら 101, 111, 100
# 1001: 1001, 1011, 1111, 1000
# 00111  00111, 00011, 00001, 00000, 01111, 11111
# 可逆 どの順でもいい?
# 再起関数?

"""
0101を考える
0000: o  1
0001: o  2
0010: x
0011: o  3
0100: o  4
0101: o  5
0110: x
0111: o  6
1000: x
1001: x
1010: x
1011: x
1100: o  7
1101: o  8
1110: x
1111: o  9

01 と 01 で分けて,00,01,11の3種 ^2 = 9
001なら000,001,011,111の4種
00011なら6種→文字数+1
"""

N = int(input())
A = input()
zero_or_one = 0
len_zero_to_one = 0
existence_zero = False
existence_one = False
end = False
answer = 1

"""
import random
A = ""
for i in range(2):
    if random.random() < 0.5:
        A += "0"
    else:
        A += "1"
print(A)
"""

for i in A:
    if i == "0":
        existence_zero = True
    if i == "1":
        existence_one = True
if not (existence_zero and existence_one):
    answer = 1
    print(answer)
    end = True

if end == False:
    while A[0] == "1":
        A = A.pop(0)
    while A != "" and A[-1] == "0":
        A = A.pop(-1)

if end == False:
    for i in A:

        # print(i, zero_or_one, len_zero_to_one, answer)  ###########
        if i == "0" and zero_or_one == 0:
            len_zero_to_one += 1
        elif i == "1" and zero_or_one == 0:
            zero_or_one = 1
            len_zero_to_one += 1
        elif i == "1" and zero_or_one == 1:
            len_zero_to_one += 1
        elif i == "0" and zero_or_one == 1:
            zero_or_one = 0
            answer *= len_zero_to_one + 1
            answer %= 998244353
            len_zero_to_one = 1
        # print(i, zero_or_one, len_zero_to_one, answer)  ###########
    answer *= len_zero_to_one + 1
    answer %= 998244353
    print(answer)