N = int(input())
B = map(int, input().split())
MOD = 998244353
MAX = 2 * 10 ** 5 + 10
# https://tjkendev.github.io/procon-library/python/math/factorial.html から拝借しています。
fact = [1] * (MAX + 1)
rfact = [1] * (MAX + 1)
r = 1
for i in range(1, MAX + 1):
    fact[i] = r = r * i % MOD
rfact[MAX] = r = pow(fact[MAX], MOD - 2, MOD)
for i in range(MAX, 0, -1):
    rfact[i - 1] = r = r * i % MOD


def comb(n, k, error=0):
    if not 0 <= k <= n:
        return error
    return fact[n] * rfact[k] * rfact[n - k] % MOD


def p2(x):
    res = 0
    while not x % 2:
        x //= 2
        res += 1
    return res


comb2 = [0] * N
for i in range(1, N):
    comb2[i] = comb2[i - 1] + p2(N - i) - p2(i)

cur = 0
ct_odd = 0
ct_even = 0
for b, c in zip(B, comb2):
    if b == -1:
        if c:
            ct_even += 1
        else:
            ct_odd += 1
        continue
    if not c:
        cur ^= b

ans = 0
for x in range(1 - cur, ct_odd + 1, 2):
    ans += comb(ct_odd, x)
    ans %= MOD
ans *= pow(2, ct_even, MOD)
ans %= MOD
print(ans)