#include <bits/stdc++.h>
using namespace std;

#define ll long long

int dx[] = {0, 1, 0, -1};
int dy[] = {1, 0, -1, 0};
int dx2[] = {1, -1, 0, 0, -1, 1, -1, 1};
int dy2[] = {0, 0, 1, -1, 1, 1, -1, -1};
int knightX[] = {-2, -2, 2, 2, 1, 1, -1, -1};
int knightY[] = {-1, 1, -1, 1, -2, 2, -2, 2};

const ll INF = 0x3f3f3f3f;
const int N = 1e6 + 5, K = 105;
const ll MOD = 1e9 + 7;

int main()
{

    ios_base::sync_with_stdio(0);
    cin.tie(0);

    int t = 1;
    cin >> t;
    while (t--) {
        int n;
        cin >> n;

        int cnt = 0, z = 0, o = 0;
        for (int i = 0; i < n; ++i) {
            int x;
            cin >> x;
            cnt += x == -1;
            z += x == 0;
            o += x == 1;
        }

        int ans = o / 3;
        o %= 3;
        int x = min(cnt / 2, o);
        ans += x;
        cnt -= 2 * x;
        ans -= cnt / 3;

        cout << ans << endl;
    }

    return 0;
}