import sys,random,bisect
from collections import deque,defaultdict
from heapq import heapify,heappop,heappush
from itertools import permutations
from math import gcd,log

from math import sqrt, ceil
from bisect import bisect_left, bisect_right
from typing import Iterable


input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())

class SegmentTree:
    def __init__(self, init_val, segfunc, ide_ele):
        n = len(init_val)
        self.segfunc = segfunc
        self.ide_ele = ide_ele
        self.num = 1 << (n - 1).bit_length()
        self.tree = [ide_ele] * 2 * self.num
        self.size = n
        for i in range(n):
            self.tree[self.num + i] = init_val[i]
        for i in range(self.num - 1, 0, -1):
            self.tree[i] = self.segfunc(self.tree[2 * i], self.tree[2 * i + 1])

    def update(self, k, x):
        k += self.num
        self.tree[k] = x
        while k > 1:
            k >>= 1
            self.tree[k] = self.segfunc(self.tree[2*k], self.tree[2*k+1])

    def query(self, l, r):
        if r==self.size:
            r = self.num

        res = self.ide_ele

        l += self.num
        r += self.num
        right = []
        while l < r:
            if l & 1:
                res = self.segfunc(res, self.tree[l])
                l += 1
            if r & 1:
                right.append(self.tree[r-1])
            l >>= 1
            r >>= 1

        for e in right[::-1]:
            res = self.segfunc(res,e)
        return res

mod = 998244353

N = int(input())
S = input()
S = S[::-1]

res = 0
for k in range(N):
    dp = [0] * (N+1)
    imos = [0] * (N+1)
    dp[0] = 1
    if k+1 <= N and S[k]=="1":
        imos[k+1] -= dp[0]
        imos[k+1] %= mod
    SUM = dp[0]
    for i in range(1,N+1):
        imos[i] += imos[i-1]
        imos[i] %= mod
        dp[i] = (SUM + imos[i])
        dp[i] %= mod
        SUM = (SUM+dp[i]) % mod
        
        if i+k+1 <= N and S[i+k]=="1":
            imos[i+k+1] -= dp[i]
            imos[i+k+1] %= mod
    res += (pow(2,N-1,mod)-dp[N]) * pow(2,k,mod)
    res %= mod

print(res)