//Author:KIT / Shunpower
//Cloud Island & Letter to Past
//May the force be with you and me.
#include <bits/stdc++.h>
#define ET return 0
#define fi first
#define se second
#define mp make_pair
#define pb emplace_back
#define ll long long
#define ull unsigned long long
#define inf INT_MAX
#define uinf INT_MIN
#define pii pair<int,int>
#define pll pair<ll,ll>
#define fr1(i,a,b) for(int i=a;i<=b;i++)
#define fr2(i,a,b) for(int i=a;i>=b;i--)
#define ld long double
#define il inline
//Quickly power: ll d=qpow(b,p>>1,k);
//Segment Tree: Memory Limit Excceed
//Segment Tree: Modify()->Pushdown()
//Mod: +M, %M, define int ll
//Mod: Don't use 998244353 instead of 1e9+7 and so on
//Don't solve a problem for too long time.
using namespace std;
const int N=1e5+10;
namespace Shun{
	int lowbit(int x){
		return x&-x;
	}
	template <typename T>
	inline void read(T &x){
	   T s=0,w=1;
	   char ch=getchar();
	   while(ch<'0'||ch>'9'){
	   		if(ch=='-'){
				w=-1;
	   		}
	        ch=getchar();
		}
	   while(ch>='0'&&ch<='9'){
	   		s=s*10+ch-'0';
			ch=getchar();
	   }
	   x=s*w;
	}
	template <typename T>
	inline void write(T x){
	    if(x<0){
	        putchar('-');
	        x=-x;
	    }
	    if(x>9){
	    	write(x/10);
		}
	    putchar(x%10+'0');
	}
}
using namespace Shun;
int tc;
int n;
int c[N];
int bol[N];
void solve(){
    cin>>n;
    fr1(i,1,n) bol[i]=0;
    fr1(i,1,n) cin>>c[i];
    fr1(i,1,n) bol[c[i]]++;
    sort(bol+1,bol+n+1);
    cout<<(bol[n]|bol[n-1]|((bol[n]&bol[n-1])-1))<<'\n';
}
int main(){
#ifdef Ltp
	freopen("hack.txt","r",stdin);
	freopen("out.txt","w",stdout);
#endif
    ios::sync_with_stdio(false);
    cin>>tc;
    while(tc--) solve();
	ET;
}
//ALL FOR Zhang Junhao.