#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPR(i, n) for (int i = n - 1; i >= 0; --i)
#define FOR(i, m, n) for (int i = m; i < n; ++i)
#define FORR(i, m, n) for (int i = m; i >= n; --i)
#define ALL(v) (v).begin(),(v).end()
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
const ll INF=1LL<<60;
const int inf=(1<<30)-1;
const int mod=1e9+7;
int dx[8]={1,0,-1,0,-1,-1,1,1};
int dy[8]={0,1,0,-1,-1,1,-1,1};
int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int T;cin >> T;
    while(T--){
        int n;cin >> n;
        vector<int> a(n);
        map<int,int> mp;
        REP(i,n){
            cin >> a[i];
            mp[a[i]]++;
        }
        ll l=0,r=n;
        while(r-l>1){
            int mid=(l+r)/2;
            vector<int> c(4);
            int cnt=0;
            bool f=false;
            for(auto x:mp){
                int num=min(x.second,mid);
                if(c[cnt]+num<mid) c[cnt]+=num;
                else{
                    c[cnt+1]=(c[cnt]+num)%mid;
                    c[cnt]=mid;
                    cnt++;
                }
                if(c[2]==mid){
                    f=true;
                    break;
                }
            }
            (f?l:r)=mid;
        }
        cout << l << endl;
    }
}