#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
vector<ll> v;
ll a[20], b[20];
map<ll, ll> mj, mo;

int main() {
    ll ans = -1, n0;
    cin >> n0;
    for (int i = 0; i < n0; ++i) {
        int tmp;
        cin >> tmp;
        // if (tmp != 0)
        v.push_back(tmp);
    }
    int n = v.size();
    if (n == 0 || n == 1) {
        cout << 0;
        return 0;
    }
    int n2 = n >> 1;
    int n1 = n - n2;
    for (int i = 0; i < n2; ++i) a[i] = v[i];
    for (int i = 0; i < n1; ++i) b[i] = v[i + n2];
    for (ll i = 0; i < (1 << n2); ++i) {
        ll sum = 0, num = 0;
        for (ll j = 0; j < n2; ++j)
            if ((i >> j) & 1) {
                sum += a[j];
                ++num;
            }
        if (num % 2 == 1)
            mj[sum]++;
        else
            mo[sum]++;
    }
    for (ll i = 0; i < (1 << n1); ++i) {
        ll sum = 0, num = 0;
        for (ll j = 0; j < n1; ++j)
            if ((i >> j) & 1) {
                sum += b[j];
                ++num;
            }
        if (num % 2 == 1)
            ans += mj[-sum];
        else
            ans += mo[-sum];
    }
    cout << ans;
}