## https://yukicoder.me/problems/no/2899

MOD = 998244353

def main():
    N = int(input())
    S = input()

    dp = [0] * (N + 1)
    dp[N] = 1

    for used, s in enumerate(S):
        new_dp = [0] * (N + 1)
        if s == "0":
            for v in range(N + 1):
                total_num = N - used
                lower = total_num - v
                if lower < 0:
                    continue
                new_dp[v] += (dp[v] * lower) % MOD
                new_dp[v] %= MOD

            x = 0
            for v in reversed(range(N + 1)):
                new_dp[v] += x
                new_dp[v] %= MOD
                x += dp[v]
                x %= MOD
        else:
            for v in range(1, N + 1):
                new_dp[v - 1] += (dp[v] * v) % MOD
                new_dp[v - 1] %= MOD
        dp = new_dp
    
    answer = 0
    for i in range(N + 1):
        answer += dp[i]
        answer %= MOD
    print(answer)














if __name__ == "__main__":
    main()