MOD = 998244353

N = int(input())
S = input()

if '1' not in S:
  print(0)
  exit()

ans, cnt = 1, 0
for i in range(N-1):
  if S[i:i+2] == "11":
    ans *= 2
    ans %= MOD
  elif S[i:i+2] == "10":
    cnt = 2
  elif S[i:i+2] == "01":
    ans *= cnt + 1
    ans %= MOD
    cnt = 0
  elif cnt:
    cnt += 1

print(ans)