import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################

ans = 0
mod = 998244353
n = ni()
s = [int(i) for i in input()]

for k in range(1, n+1):
    dp0 = [0] * (n+1)
    dp0[0] = 1
    dp1 = [0] * (n+1)
    rui0 = [0] * (n+1)
    rui0[0] = 1
    rui1 = [0] * (n+1)
    for i in range(1, n+1):
        if i-k >= 0 and s[i-k]:
            dp1[i] = (rui0[i-k]+rui1[i-1])%mod
            dp0[i] = (rui0[i-1]-rui0[i-k])%mod
        else:
            dp1[i] = rui1[i-1]
            dp0[i] = rui0[i-1]
        rui0[i] = (rui0[i-1] + dp0[i])%mod
        rui1[i] = (rui1[i-1] + dp1[i])%mod
    ans += dp1[-1] * pow(2, k-1, mod)%mod
    ans %= mod
    #print(dp1[-1])
print(ans)