#include <iostream>
#include <map>

int a[50];
using namespace std;

int main() {
    int n;
    cin >> n;
    map<int, int> mp, mp1, mp2;
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    int sum = 0;
    int tol, t, x;
    int ans = 0;
    for (int mask = 0, tol = 1 << (n / 2); mask < tol; mask++) {
        t = 0;
        sum = 0;
        for (int i = 0; i < (n / 2); i++) {
            if ((mask >> i) & 1) {
                sum = sum + a[i];
                t++;
            }
        }
        if (t % 2 == 1)
            mp1[sum]++;
        if (t % 2 == 0)
            mp2[sum]++;
    }
    for (int mask = 0, tol = 1 << (n - n / 2); mask < tol; mask++) {
        sum = 0;
        x = 0;
        for (int i = 0; i < (n - n / 2); i++) {
            if ((mask >> i) & 1) {
                sum = sum + a[i + n / 2];
                x++;
            }
        }
        if (x % 2 == 0) {
            ans = ans + mp2[-sum];
        }
        if (x % 2 == 1) {
            ans = ans + mp1[-sum];
        }
    }
    cout << ans - 1;
    return 0;
}