/**
 *    author:   Binoy Barman
 *    created:  2025-01-02 20:41:13
**/

#include<bits/stdc++.h>
#ifdef LOCAL
#include "debug/trace.hpp"
#else
#define dbg(...) 42
#define print(...) 42
#endif
using namespace std;
using ll = long long;
const int mod = 1e9 + 7;
const int inf = 1e9;

#define int long long
#define nl '\n'
#define all(v) v.begin(), v.end()
#define Testcase_Handler int tts, tc = 1; cin >> tts; hell: while(tts--)
#define uniq(v) sort(all(v)), v.resize(distance(v.begin(), unique(v.begin(), v.end())))
template<class T> using minheap = priority_queue<T, vector<T>, greater<T>>;
template<typename T> istream& operator>>(istream& in, vector<T>& a) {for(auto &x : a) in >> x; return in;};
template<typename T> ostream& operator<<(ostream& out, vector<T>& a) {bool first = true;for(auto &x : a) {if(!first) out << ' ';first = false;out << x;}return out;};

namespace Dark_Lord_Binoy {
void preprocess() {}
void setup() {
    ios_base::sync_with_stdio(false); 
    cin.tie(nullptr);
    preprocess();

    #ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #endif
}
}

int32_t main() {
    Dark_Lord_Binoy::setup();
    Testcase_Handler {
        int n;
        cin >> n;
        int one = 0, zero = 0, neg = 0;
        for (int i = 0; i < n; i++) {
            int x;
            cin >> x;
            if(x == 1) one++;
            else if(x == 0) zero++;
            else neg++;
        }
        int ans = 0;
        while(n > 0) {
            if(one >= 1 && neg >= 2) {
                ans++;
                one--;
                neg -= 2;
            } else if(zero >= 1 && neg >= 2) {
                zero--;
                neg -= 2;
            } else if(zero >= 2 && neg >= 1) {
                zero -= 2;
                neg--;
            } else if(one >= 2 && neg >= 1) {
                ans--;
                one -= 2;
                neg--;
            } else if(one >= 2 && zero >= 1) {
                one -= 2;
                zero--;
            } else if(zero >= 2 && one >= 1) {
                zero -= 2;
                one--;
            } else if(one >= 3) {
                ans++;
                one -= 3;
            } else if(zero >= 3) {
                zero -= 3;
            } else if(neg >= 3) {
                ans--;
                neg -= 3;
            }
            n -= 3;
        }
        cout << ans << nl;
    }

    print(_Time_);
    return 0;
}