#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <string>
#include <cstring>
#include <set>
#include <map>
#include <sstream>
using namespace std;
struct oj {
    int x;
    int y;
};

int main() {
    map<long long, oj> tong;
    long long sum, a, b, c;
    int n, ans = 0, m;
    cin >> n;
    long long *list = new long long[n];
    for (long long i = 0; i < n; i++) {
        cin >> list[i];
    }
    a = pow(2, n / 2);
    b = pow(2, n / 2 + 1);
    for (long long i = 0; i < a; i++) {
        sum = 0;
        m = 0;
        for (long long j = 0; j < n / 2; j++) {
            if (i & (1 << j)) {
                sum += list[j];
                m++;
            }
        }
        if (!tong.count(sum))
            tong[sum].x = tong[sum].y = 0;
        if (m % 2 == 0)
            tong[sum].y++;
        tong[sum].x++;
    }
    c = a;
    if (n % 2 != 0)
        c = b;
    for (long long i = 0; i < c; i++) {
        sum = 0;
        m = 0;
        for (long long j = 0; j < n - n / 2; j++) {
            if (i & (1 << j)) {
                sum += list[j + n / 2];
                m++;
            }
        }
        if (!tong.count(-sum))
            tong[-sum].x = 0;
        if (m % 2 == 0)
            ans += tong[-sum].y;
        else
            ans += tong[-sum].x - tong[-sum].y;
    }
    cout << ans - 1;
    return 0;
}