import sys
input = sys.stdin.readline

mod = 998244353
N = int(input())
S = list(map(int, input().rstrip()))
pow2 = [1]*N
for i in range(1, N):
    pow2[i] = 2*pow2[i-1] % mod
ans = 0
for k in range(N):
    dp = [0] * (N+1)
    dp[0] = 1
    cumsum = [0] * (N+2)
    cnt = 0
    for i in range(1, N+1):
        cumsum[i] = (cumsum[i-1] + dp[i-1]) % mod

        if i-k-1 >= 0 and S[i-k-1] == 1:
            dp[i] = (cumsum[i] - cumsum[i-k]) % mod
            cnt = (cnt + cumsum[i-k] * pow2[max(0, N-i-1)]) % mod
        else:
            dp[i] = cumsum[i]
    ans = (ans + cnt * pow2[k]) % mod
print(ans)