import sys, math
sys.set_int_max_str_digits(0)
from collections import deque
N = list(input())
A = list(input())
A = deque(A)
while A and A[0] == '1':
    A.popleft()
while A and A[-1] == '0':
    A.pop()

A = list(A)
if len(A) == 0:
    exit(print(1))

from itertools import groupby
def runLengthEncode(S):
    grouped = groupby(S)
    res = []
    for k, v in grouped:
        res.append((k, int(len(list(v)))))
    return res

data = runLengthEncode(A)
L = len(data)

MOD = 998244353
ans = 1
for i in range(L//2):
    _, zero = data[2*i]
    _, one = data[2*i+1]
    ans *= zero+one+1
    if ans >= MOD:
        ans %= MOD

print(ans%MOD)