SIZE=10**5+1; MOD=10**9+7 #998244353 #ここを変更する

inv = [0]*SIZE  # inv[j] = j^{-1} mod MOD
fac = [0]*SIZE  # fac[j] = j! mod MOD
finv = [0]*SIZE # finv[j] = (j!)^{-1} mod MOD
fac[0] = fac[1] = 1
finv[0] = finv[1] = 1
for i in range(2,SIZE):
    fac[i] = fac[i-1]*i%MOD
finv[-1] = pow(fac[-1],MOD-2,MOD)
for i in range(SIZE-1,0,-1):
    finv[i-1] = finv[i]*i%MOD
    inv[i] = finv[i]*fac[i-1]%MOD

def choose(n,r): # nCk mod MOD の計算
    if 0 <= r <= n:
        return (fac[n]*finv[r]%MOD)*finv[n-r]%MOD
    else:
        return 0


def popcount(i): # i < 2^32
    i = i - ((i >> 1) & 0x55555555)
    i = (i & 0x33333333) + ((i >> 2) & 0x33333333)
    return (((i + (i >> 4) & 0xF0F0F0F) * 0x1010101) & 0xffffffff) >> 24

n = int(input())
*a, = map(int,input().split())
p2 = [1]*(n+100)
for i in range(1,n+100):
    p2[i] = p2[i-1]*2%MOD

def check(c,x,y):
    r = 0
    sgn = 1
    for i in range(1,c+1)[::-1]:
        r += sgn*choose(c,i)*pow(p2[i],x,MOD)%MOD*pow(p2[i]-1,y,MOD)
        r %= MOD
        sgn *= -1
    #print(c,x,y,r)
    return r


v = c = 0
ans = 1
for ai in a:
    c += 1
    if ai == -1:
        continue
    else:
        if v|ai != ai:
            ans = 0
            break
        x = popcount(v&ai)
        y = popcount(v^ai)
        #print(x,y)
        ans *= check(c,x,y)
        ans %= MOD
        c = 0
        v = ai
    #print(ans)
if c:
    ans *= pow(p2[30]-1,c,MOD)
    ans %= MOD

print(ans)