N=int(input())
S=input()
if S=='0'*N:
  print(0)
  exit()
from collections import deque
d=deque()
for s in S:
  d.append(s)
  
while d[0]=='0':
  d.popleft()
while d[-1]=='0':
  d.pop()
  
d.popleft()
ans=1;now=0
while d:
  c=d.popleft()
  if c=='0':
    now+=1
  else:
    ans*=now+2
    now=0
    ans%=998244353
print(ans)