#include <bits/stdc++.h>
using namespace std;
map<int, int> mp[2];
int main() {
    int n, a[40], arr[2][200000], tot[2], ans = 0;
    memset(tot, 0, sizeof(tot));
    scanf("%d", &n);
    for (int i = 0; i < n; i++) scanf("%d", &a[i]);
    int left = 1 << (n / 2), right = 1 << (n - n / 2);
    for (int i = 1; i < left; i++) {
        int sum = 0, len = 0;
        for (int j = 0; j < n / 2; j++) {
            if ((1 << j) & i) {
                sum += a[j];
                len++;
            }
        }
        mp[len & 1][sum]++;
        if (sum == 0 && (len & 1) == 0)
            ans++;
    }
    for (int i = 0; i < 2; i++) sort(arr[i], arr[i] + tot[i]);
    for (int i = 1; i < right; i++) {
        int sum = 0, len = 0;
        for (int j = 0; j < n - n / 2; j++) {
            if ((1 << j) & i) {
                sum += a[j + n / 2];
                len++;
            }
        }
        if (sum == 0 && (len & 1) == 0)
            ans++;
        ans += mp[len & 1][-sum];
    }
    printf("%d", ans);
    return 0;
}