import sys

def solve():
    data = sys.stdin.read().split()
    if not data:
        return
    n = int(data[0])
    s = data[1]
    mod = 998244353
    f = [0] * (n + 1)
    f[0] = 1
    for i in range(1, n + 1):
        f[i] = f[i-1]
        if i >= 2 and s[i-2] == '0' and s[i-1] == '1':
            f[i] = (f[i] + 2 * f[i-2]) % mod
    print(f[n])

if __name__ == "__main__":
    solve()