from bisect import bisect_left
MOD = 998244353
N = int(input())
S = [1]+list(map(int,list(input())))
A = []
for i in range(N+1):
    if S[i]==1:
        A.append(i)
dp = [0]*(N+1)
if S[1]==1:
    dp[1] = 1
for i in range(2,N+1):
    if S[i]==0:
        dp[i] = dp[i-1]
    else:
        ind = bisect_left(A,i)
        if ind-1>0:
            dp[i] = (dp[i-1]*(i-A[ind-1]+1))%MOD
        else:
            dp[i] = 1
print(dp[N])