#include<bits/stdc++.h>
using namespace std;
const int N=200005;
int t,n,a[N],c[N],ans;
vector<int>v;
signed main(){
//	cin.tie(0),cout.tie(0),ios::sync_with_stdio(0);
	cin>>t;
	while(t--){
		cin>>n;v.clear();
		for(int i=1;i<=n;++i)c[i]=0;
		for(int i=1,x;i<=n;++i)cin>>x,c[x]++;
		for(int i=1;i<=n;++i)if(c[i])v.push_back(c[i]);
		sort(v.begin(),v.end());
		reverse(v.begin(),v.end());
		ans=v[0];
		if(v.size()==1){cout<<ans<<"\n";continue;}
		int mx=0;
		for(int i=30;i>=0;--i)if((1<<i)&v[0])mx=max(mx,i);
		for(int j=1;j<v.size();++j){
			int x=v[j],y=v[0],tmp=0;
			for(int i=mx;i>=0;--i)
				if(((1<<i)&x)&&((1<<i)&y)){tmp|=((1<<((i+1)))-1);break;}
				else if(((1<<i)&x)||((1<<i)&y))tmp|=(1<<i);
			ans=max(ans,tmp);
		}
		cout<<ans<"\n";
	}
	return 0;
}
/*
*/

answer.code: In function ‘int main()’:
answer.code:27:26: error: no match for ‘operator<’ (operand types are ‘std::basic_ostream<char>’ and ‘const char [2]’)
   27 |                 cout<<ans<"\n";
      |                 ~~~~~~~~~^~~~~
      |                     |     |
      |                     |     const char [2]
      |                     std::basic_ostream<char>
In file included from /usr/include/c++/13/regex:68,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:181,
                 from answer.code:1:
/usr/include/c++/13/bits/regex.h:1143:5: note: candidate: ‘template<class _BiIter> bool std::__cxx11::operator<(const sub_match<_BiIter>&, const sub_match<_BiIter>&)’
 1143 |     operator<(const sub_match<_BiIter>& __lhs, const sub_match<_BiIter>& __rhs)
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1143:5: note:   template argument deduction/substitution failed:
answer.code:27:27: note:   ‘std::basic_ostream<char>’ is not derived from ‘const std::__cxx11::sub_match<_BiIter>’
   27 |                 cout<<ans<"\n";
      |                           ^~~~
/usr/include/c++/13/bits/regex.h:1224:5: note: candidate: ‘template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator<(__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&, const sub_match<_BiIter>&)’
 1224 |     operator<(const __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1224:5: note:   template argument deduction/substitution failed:
answer.code:27:27: note:   ‘std::basic_ostream<char>’ is not derived from ‘std::__cxx11::__sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>’
   27 |                 cout<<ans<"\n";
      |                           ^~~~
/usr/include/c++/13/bits/regex.h:1317:5: note: candidate: ‘template<class _Bi_iter, class _Ch_traits, class _Ch_alloc> bool std::__cxx11::operator<(const sub_match<_BiIter>&, __sub_match_string<_Bi_iter, _Ch_traits, _Ch_alloc>&)’
 1317 |     operator<(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1317:5: note:   template argument deduction/substitution failed:
answer.code:27:27: note:   ‘std::basic_ostream<char>’ is not derived from ‘const std::__cxx11::sub_match<_BiIter>’
   27 |                 cout<<ans<"\n";
      |                           ^~~~
/usr/include/c++/13/bits/regex.h:1391:5: note: candidate: ‘template<class _Bi_iter> bool std::__cxx11::operator<(const typename std::iterator_traits<_Iter>::value_type*, const sub_match<_BiIter>&)’
 1391 |     operator<(typename iterator_traits<_Bi_iter>::value_type const* __lhs,
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1391:5: note:   template argument deduction/substitution failed:
answer.code:27:27: note:   mismatched types ‘const std::__cxx11::sub_match<_BiIter>’ and ‘const char [2]’
   27 |                 cout<<ans<"\n";
      |                           ^~~~
/usr/include/c++/13/bits/regex.h:1485:5: note: candidate: ‘template<class _Bi_iter> bool std::__cxx11::operator<(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type*)’
 1485 |     operator<(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1485:5: note:   template argument deduction/substitution failed:
answer.code:27:27: note:   ‘std::basic_ostream<char>’ is not derived from ‘const std::__cxx11::sub_match<_BiIter>’
   27 |                 cout<<ans<"\n";
      |                           ^~~~
/usr/include/c++/13/bits/regex.h:1560:5: note: candidate: ‘template<class _Bi_iter> bool std::__cxx11::operator<(const typename std::iterator_traits<_Iter>::value_type&, const sub_match<_BiIter>&)’
 1560 |     operator<(typename iterator_traits<_Bi_iter>::value_type const& __lhs,
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1560:5: note:   template argument deduction/substitution failed:
answer.code:27:27: note:   mismatched types ‘const std::__cxx11::sub_match<_BiIter>’ and ‘const char [2]’
   27 |                 cout<<ans<"\n";
      |                           ^~~~
/usr/include/c++/13/bits/regex.h:1660:5: note: candidate: ‘template<class _Bi_iter> bool std::__cxx11::operator<(const sub_match<_BiIter>&, const typename std::iterator_traits<_Iter>::value_type&)’
 1660 |     operator<(const sub_match<_Bi_iter>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/13/bits/regex.h:1660:5: note:   template argument deduction/substitution failed:
answer.code:27:27: note:   ‘std::basic_ostream<char>’ is not derived from ‘const std::__cxx11::sub_match<_BiIter>’
   27 |                 cout<<ans<"\n";
      |                           ^~~~
In file included from /usr/include/c++/13/bits/stl_algobase.h:64,
                 from /usr/include/c++/13/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:51:
/usr/include/c++/13/bits/stl_pair.h:835:5: note: candidate: ‘template<class _T1, class _T2> constexpr bool std::operator<(const pa...