MOD = 10**9 + 7

fact_range = 10 ** 6
fact = [1] * (fact_range + 1)
for i in range(0, fact_range):
    fact[i+1] = fact[i] * (i + 1) % MOD

ifact = [1] * (fact_range + 1)
ifact[fact_range] = pow(fact[fact_range], MOD - 2, MOD)
for i in range(fact_range, 0, -1):
    ifact[i-1] = ifact[i] * i % MOD

def comb(n, k):
    if k < 0 or n < k:
        return 0
    else:
        return fact[n] * ifact[n-k] % MOD * ifact[k] % MOD

n = int(input())
b = [0] + list(map(int, input().split()))
now = b[n]
r = n
ans = 1
for i in range(n)[::-1]:
    if b[i] == -1:
        continue
    if now & b[i] != b[i]:
        print(0)
        exit()
    L = r - i
    diff = bin(now ^ b[i]).count('1')
    fr = bin(b[i]).count('1')
    #print(i, diff, ln)
    tot = 0
    for ln in range(L + 1):
        t = 0
        for k in range(diff + 1):
            if k % 2 == 0:
                t += comb(diff, k) * pow(2, (diff - k) * ln, MOD) * pow(2, fr * ln, MOD)
            else:
                t -= comb(diff, k) * pow(2, (diff - k) * ln, MOD) * pow(2, fr * ln, MOD)
            #print(k, t)
        #print(t)
        if (L - ln) % 2 == 0:
            tot += comb(L, ln) * t
        else:
            tot -= comb(L, ln) * t
        tot %= MOD
    ans = ans * tot % MOD
    now = b[i]
    r = i
print(ans)