#include <bits/stdc++.h>
using namespace std;
#define SC               scanf
#define PF               printf
#define ull              unsigned long long
#define ld               long double
#define F                first
#define S                second
#define pb               push_back
#define sort_a(a)        sort(a.begin(),a.end());
#define sort_d(a)        sort(a.rbegin(),a.rend());
#define READ(f)          freopen(f, "r", stdin)
#define WRITE(f)         freopen(f, "w", stdout)
#define rev(s)           reverse(s.begin(),s.end())
#define P(ok)            cout << (ok ? "YES\n": "NO\n")
#define __Heart__              ios_base :: sync_with_stdio(false); cin.tie(NULL);
#define ll long long
typedef pair< ll , ll>                   PII;
void solve()
{
    int n , minusOne = 0 , plusOne = 0 , zero = 0 , x ; cin >> n ;  ;
    for(int i = 0 ; i < n ; i++) {
        cin >> x ;
        if(x == 0) zero++ ;
        else if(x == 1) plusOne++ ;
        else minusOne++ ;
    }
    if(zero) {
        cout << 0 << "\n" ;
        return ;
    }

    int adding = min(minusOne / 2 , plusOne) ;
    int deducting = 0 ;
    minusOne -= (adding * 2) ;
    plusOne -= adding ;
    if(minusOne){
        deducting = minusOne / 3 ;
        minusOne %= 3 ;
    }
    if(plusOne) {
        adding += (plusOne / 3) ;
        plusOne %= 3 ;
    }
    plusOne += minusOne ;
    plusOne /= 3 ;
    deducting += plusOne ;
    adding -= deducting ;
    cout << adding << "\n" ;
}
int main()
{
     __Heart__
     int t ; cin >> t ; while(t--) solve() ;
}