#include<bits/stdc++.h>
using namespace std;
// #define int long long
#define rep(i,j,k) for(int i=(j);i<=(k);i++)
#define per(i,j,k) for(int i=(j);i>=(k);i--)
#define pb push_back
#define mp make_pair
#define fi first
#define se second
typedef vector<int> vi;
typedef pair<int,int> pi;

void solve(){
    int n; cin>>n;
    vi a(n+1);
    rep(i,0,n-1){
        cin>>a[i];
    }
    sort(a.begin(), a.begin()+n);
    a[n]=-1;
    int cnt=1;
    priority_queue<int, vi, greater<int>> Q;
    rep(i,1,n){
        if(a[i]!=a[i-1]){
            Q.push(cnt);
            int x=Q.top();
            Q.pop();
            if(x>=0){
                Q.push(x-1);
            }
            cnt=0;
        }
        cnt++;
    }
    int ans=0;
    while(!Q.empty()){
        ans+=max(0, Q.top());
        Q.pop();
    }
    cout<<ans<<'\n';
}
signed main(){
    #ifndef ONLINE_JUDGE
    assert(freopen(".in","r",stdin));
    // assert(freopen(".out","w",stdout));
    #endif
    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);

    int t; cin>>t;
    while(t--){
        solve();
    }
}