from collections import deque

N = int(input())
A = input()
M = 998244353

# 次を0に / 前を1に
# 01101; 00101, 00001, 00000
#               00011, 00111, 11111
#        01100, 00100
#        11101, 11100
#        01111

s : set[str] = set()
find = deque([A])
while find:
    h = find.popleft()
    if h in find:
        continue
    s.add(h)
    for i in range(N-1):
        if h[i] == '0' and h[i+1] == '1':
            l = h[:i]
            r = h[i+2:]
            p = l + '00' + r
            if p not in s:
                find.append(p)
            p = l + '11' + r
            if p not in s:
                find.append(p)
print(len(s) % M)