import sys
import re

N = input().strip()
A = input().strip()

result = 0
dic = [int(A, 2)]
test = [int(A, 2)]
while True:
    target = test[0]
    str_target = bin(target)[2:].zfill(int(N))
    index = [m.start() for m in re.finditer("01", str_target)]
    num = len(index)
    for i in range(num):
        target_ind = index[i]

        target_change1 = str_target[:target_ind] + "1" + str_target[target_ind+1:]
        if not(int(target_change1, 2) in dic):
            dic.append(int(target_change1, 2))
            test.append(int(target_change1, 2))

        target_change0 = str_target[:target_ind+1] + "0" + str_target[target_ind+2:]
        if not(int(target_change0, 2) in dic):
            dic.append(int(target_change0, 2))
            test.append(int(target_change0, 2))

    test.pop(0)
    result += 1
    if test == []:
        break

modulo = result % 998244353
print(modulo)