#include <bits/stdc++.h>
#include<grader.h>
using namespace std;
#define ll long long
#define endl "\n"
#define INF 1000000000
#define LINF 1000000000000000LL
#define pb push_back
#define all(x) x.begin(), x.end()
#define len(s) (int)s.size()
#define test_case { int t; cin>>t; while(t--)solve(); }
#define input(n, v) {for(int i = 0;i<n;i++) cin>>v[i];}
#define output(n, v) {for(int i = 0;i<n;i++) cout<<v[i]<<" "; cout<<endl;}
#define single_case solve();
#define line cout<<"------------"<<endl;
#define ios { ios_base::sync_with_stdio(false); cin.tie(NULL); }
using namespace std;
void solve(int n)
{
int k = 30;
if(n<=50)
k = 25;
int best = 0;
int ans = -1;
mt19937 mt_rand(time(0));
for(int i = 0;i<k;i++)
{
int s = (mt_rand())%n+1;
int w = kth(s);
int c = cnt(w);
if(c>best)
{
best = c;
ans = w;
}
}
if(best>n/3)
say_answer(ans);
else
say_answer(-1);
}
