#include <bits/stdc++.h>
#define F(i, n, m) for (int i = n; i < m; i++)
typedef unsigned long long ull;
typedef long long ll;
using namespace std;
inline int read() {
    int num = 0;
    char c;
    bool flag = false;
    while ((c = getchar()) == ' ' || c == '\n' || c == '\r')
        ;
    if (c == '-')
        flag = true;
    else
        num = c - '0';
    while (isdigit(c = getchar())) num = num * 10 + c - '0';
    return (flag ? -1 : 1) * num;
}
int a[30], ans;
int n;
void dfs(int i, int sum, int num) {
    if (i == n) {
        if (sum == 0 && num % 2 == 0 && num != 0)
            ans++;
        return;
    }
    dfs(i + 1, sum, num);
    dfs(i + 1, sum + a[i], num + 1);
}
int main() {
    std::ios::sync_with_stdio(false);
    n = read();
    F(i, 0, n) a[i] = read();
    dfs(0, 0, 0);
    cout << ans;
    return 0;
}