import sys
#sys.setrecursionlimit(5*10**5)
input = sys.stdin.readline
sys.set_int_max_str_digits(0)
from collections import defaultdict, deque, Counter
from heapq import heappop, heappush
from bisect import bisect_left, bisect_right
from math import gcd, lcm, factorial, perm, comb
from itertools import product, permutations
from functools import lru_cache #@lru_cache(maxsize=128)
#重複あり：list(product(list('123'),repeat = 2)),重複なし：list(permutations(list('123')))
MOD = 998244353

n = int(input())
l = list(input())
s=1
cnt=1
if l[1]=='0':
    for i in range(1,n):
        if l[i]=='1':
            cnt+=1
            s*=cnt
            cnt=1
        else:
            cnt+=1
        s%=MOD
else:
    for i in range(2,n):
        if l[i]=='1':
            cnt+=1
            s*=cnt
            cnt=1
        else:
            cnt+=1
        s%=MOD
print(s)