n = int(input())
B = list(map(int,input().split()))
mod = 10**9+7

num = 0
for b in B:
    if b != -1:
        if b|num != b:
            print(0)
            exit()
        num = b

fact = [1,1]
finv = [1,1]
inv = [0,1]
pow2 = [1]
for i in range(n*40):
    pow2.append(pow2[-1]*2%mod)
for i in range(2,max(40,n)+5):
    fact.append((fact[-1]*i)%mod)
    inv.append((inv[mod%i]*(mod-mod//i))%mod)
    finv.append((finv[-1]*inv[-1])%mod)
 
def nCr(n,r,mod):
    if r > n:
        return 0
    else: 
        return fact[n]*finv[r]*finv[n-r]%mod

def calc(x,all,le):
    ind = 1
    base = 0

    for i in range(x+1):
        count = 0
        mi = 1
        for j in range(le+1):
            count += mi*nCr(le,j,mod)*pow2[(all-i)*(le-j)]%mod
            count %= mod
            mi *= -1
        base += ind*nCr(x,i,mod)*count%mod
        base %= mod
        ind *= -1

    return base


ans = 1
num = 0
now = 0
for b in B:
    num += 1
    if b == -1:
        continue
    x = b^now
    all = bin(b).count("1")
    c = 0
    for i in range(40):
        if x >> i & 1:
            c += 1
    ans *= calc(c,all,num)
    ans %= mod
    num = 0
    now = b
print(ans)