#include <bits/stdc++.h>
using namespace std;
map<long long, long long> mp1;
map<long long, long long> mp2;
int main() {
    long long n, x;
    long long ans = 0;
    vector<long long> a, b;
    cin >> n;
    for (long long i = 0; i < n; i++) {
        cin >> x;
        if (i < n / 2)
            a.push_back(x);
        else
            b.push_back(x);
    }
    for (long long mask = 0; mask < 1 << a.size(); mask++) {
        long long sum = 0;
        long long tot = 0;
        for (long long i = 0; i < a.size(); i++) {
            if ((mask >> i) & 1) {
                sum += a[i];
                tot++;
            }
        }
        if (tot % 2 == 0)
            mp2[sum]++;
        else
            mp1[sum]++;
    }

    for (long long mask = 0; mask < 1 << b.size(); mask++) {
        long long sum = 0;
        long long tot = 0;
        for (long long i = 0; i < b.size(); i++) {
            if ((mask >> i) & 1) {
                sum += b[i];
                tot++;
            }
        }
        if (tot % 2 == 0) {
            map<long long, long long>::iterator it = mp2.find(-sum);
            if (it != mp2.end()) {
                // cout << it->first << " " << it->second << endl;
                ans += it->second;
            }
        } else {
            map<long long, long long>::iterator it = mp1.find(-sum);
            if (it != mp1.end()) {
                // cout << it->first << " " << it->second << endl;
                ans += it->second;
            }
        }
    }

    /*map<int, int>::iterator it;
    for (it = mp1.begin(); it != mp1.end(); it++)
        cout << it->first << " " << it->second << endl;*/
    cout << ans - 1;
    return 0;
}