M=998244353
n=int(input())
s=list(map(int,input()+"0"))
for i in range(n):
  s[i]+=s[i-1]
q=[0]*(n+1)
q[0]=1
q[1]=-1
l=0
for i in range(n+1):
  q[i]+=q[i-1]
  q[i]%=M
  l=max(l,i)
  while l+1<=n and s[l+1-1]-s[i-1]==0:
    l+=1
  if l+1<=n and s[l+1-1]-s[i-1]>0:
    q[l+1]+=q[i]
    q[l+1]%=M
print(q[n])