n = int(input())
A = list(map(int, input().split()))
A2 = A[len(A) // 2:]
del A[len(A) // 2:]
odd = []
even = []
ans = -1


def search(li, k):
    if not li:
        return [0, 0]
    else:
        l, r = 0, len(li)
        if li[l][0] > k:
            return [0, 0]
        else:
            while r - l > 1:
                mid = (l + r) // 2
                if li[mid][0] > k:
                    r = mid
                elif li[mid][0] < k:
                    l = mid
                else:
                    return [mid, 1]
            if li[l][0] < k:
                return [r, 0]
            else:
                return [l, 1]


for i in range(2 ** len(A2)):
    b = bin(i)[2:]
    count = 0
    s = 0
    for j in range(len(b)):
        if b[-1-j] == '1':
            count += 1
            s += A2[j]
    if count % 2 == 1:
        chi = search(odd, s)
        if chi[1] == 1:
            odd[chi[0]][1] += 1
        else:
            odd.insert(chi[0], [s, 1])
    else:
        chi = search(even, s)
        if chi[1] == 1:
            even[chi[0]][1] += 1
        else:
            even.insert(chi[0], [s, 1])
for i in range(2 ** len(A)):
    b = bin(i)[2:]
    count = 0
    s = 0
    for j in range(len(b)):
        if b[-1 - j] == '1':
            count += 1
            s += A[j]
    if count % 2 == 1:
        chi = search(odd, -s)
        if chi[1] == 1:
            ans += odd[chi[0]][1]
    else:
        chi = search(even, -s)
        if chi[1] == 1:
            ans += even[chi[0]][1]
print(ans)