# dp[i][bool] i まで見たとき、 切った状態で 1 を含むかどうかの数
N = int(input())
S = list(input())
mod = 998244353
dp =  [[0,0] for _ in range(N+1)]
dp[0][0] = 1 
for i in range(N):
    if S[i] == "1":
        dp[i+1][1] = dp[i][0]+dp[i][1]
        dp[i+1][0] = dp[i][0]+dp[i][1]
    else:
        dp[i+1][1] = dp[i][1]
        dp[i+1][0] = dp[i][0]+dp[i][1]
    dp[i+1][0] %= mod
    dp[i+1][1] %= mod
print(dp[-1][1]%mod)