#include "bits/stdc++.h"
#define pb push_back
#define ls (i << 1)
#define rs ((i << 1) + 1)
using namespace std;
typedef long long ll;
vector<ll> a, b;
map<ll, int> mp[2];
ll ans = 0;
int main() {
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        ll x;
        cin >> x;
        if (i <= n / 2)
            a.pb(x);
        else
            b.pb(x);
    }
    int l1 = (1 << ((int)a.size())), l2 = (1 << ((int)b.size()));
    // cout << l1 << endl;
    for (int i = 0; i < l1; i++) {
        ll sum = 0;
        for (int j = 0; (i >> j) > 0; j++) {
            sum = sum + ((i >> j) & 1) * a[j];
        }
        // printf("%lld\n", sum);
        mp[(__builtin_popcount(i) & 1)][sum]++;
    }
    for (int i = 0; i < l2; i++) {
        ll sum = 0;
        for (int j = 0; (i >> j) > 0; j++) {
            sum = sum + ((i >> j) & 1) * b[j];
        }
        if (mp[(__builtin_popcount(i) & 1)].find(-sum) != mp[(__builtin_popcount(i) & 1)].end())
            ans = ans + mp[(__builtin_popcount(i) & 1)][-sum];
    }
    cout << ans - 1;
    return 0;
}