N = int(input())
S = input()
cum = [0]*(N+1)
for i in range(N):
	cum[i+1]=cum[i]+int(S[i])
cnt = [0]*(N+1)
for ci in cum: cnt[ci]+=1

c1  = cum[-1]
dp = [0]*(N+1) ; dp[0]=1
cum_dp = [0]*(N+1) ; cum_dp[0]=1

mod = 998244353
for i in range(1,N+1):
	dp[i] = (cum_dp[i-1]*cnt[i]) % mod
	cum_dp[i] = (cum_dp[i-1]+dp[i]) % mod
print(cum_dp[c1-1])