#include <iostream>
#include <map>
#include <algorithm>
using namespace std;
int main() {
    ios::sync_with_stdio(false);  //关cin同步；加速
    int n;
    cin >> n;
    int c1[20];
    int *sum1 = new int[1 << (n / 2)], *cnt1 = new int[1 << (n / 2)];
    int result = 0;
    for (int i = 0; i < n / 2; i++) cin >> c1[i];
    map<int, int> a1, a2;
    for (int i = 0; i < (1 << (n / 2)); i++) {  //折半枚举二进制的位数,n个数
        sum1[i] = 0, cnt1[i] = 0;
        for (int j = 0; j < n / 2; j++) {
            if (i & (1 << j))
                sum1[i] += c1[n / 2 - 1 - j], cnt1[i]++;
        }
    }
    for (int i = 0; i < (1 << (n / 2)); i++) {
        if (a1.find(sum1[i]) == a1.end() && cnt1[i] % 2 == 1)
            a1[sum1[i]] = 0;
        if (a2.find(sum1[i]) == a2.end() && cnt1[i] % 2 == 0)
            a2[sum1[i]] = 0;
        if (a1.find(sum1[i]) != a1.end() && cnt1[i] % 2 == 1)
            a1[sum1[i]]++;  //分元素个数的奇偶
        if (a2.find(sum1[i]) != a2.end() && cnt1[i] % 2 == 0)
            a2[sum1[i]]++;
    }
    //下面解决下一半
    delete[] sum1, delete[] cnt1;
    int c2[20];
    for (int i = 0; i < n / 2; i++) cin >> c2[i];
    if (n % 2 == 1)
        cin >> c2[n / 2];
    int *sum2 = new int[1 << (n / 2)], *cnt2 = new int[1 << (n / 2)];
    for (int i = 0; i < (1 << (n / 2)); i++) {
        sum2[i] = 0, cnt2[i] = 0;
        for (int j = 0; j < n / 2; j++) {
            if (i & (1 << j))
                sum2[i] += c2[n / 2 - 1 - j], cnt2[i]++;
        }
    }
    for (int i = 0; i < (1 << (n / 2)); i++) {
        if (cnt2[i] % 2 == 1 && a1.find(-sum2[i]) != a1.end())
            result += a1[-sum2[i]];
        if (cnt2[i] % 2 == 0 && a2.find(-sum2[i]) != a2.end())
            result += a2[-sum2[i]];
    }
    if (n % 2 == 1) {  //如果是奇数 就将最后一个拿在最后单独讨论 没有选的前面已经讨论过了，这里直接选上。
        for (int i = 0; i < (1 << (n / 2)); i++) sum2[i] += c2[n / 2], cnt2[i]++;
        for (int i = 0; i < (1 << (n / 2)); i++) {
            if (cnt2[i] % 2 == 1 && a1.find(-sum2[i]) != a1.end())
                result += a1[-sum2[i]];
            if (cnt2[i] % 2 == 0 && a2.find(-sum2[i]) != a2.end())
                result += a2[-sum2[i]];
        }
    }
    delete[] sum2, delete[] cnt2;
    cout << result - 1;
    return 0;
}