#include "grader.h"
//#include "grader.cpp"
#include <bits/stdc++.h>
using namespace std;
//#define int long long
//#define ld long double
#define show(x,y) cout << y << " " << #x << endl;
#define show2(x,y,i,j) cout << y << " " << #x << " " << j << " " << #i << endl;
#define show3(x,y,i,j,p,q) cout << y << " " << #x << " " << j << " " << #i << " " << q << " " << #p << endl;
#define show4(x,y) for(auto it:y) cout << it << " "; cout << #x << endl;
typedef pair<int,int>pii;
//typedef pair<ld,ld>pi2;
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
int ran(int index){return rng()%index;}
//say_answer()
//cnt()
//kth()
void solve(int n){
vector<int>v;
for(int x=1;x<=n;x++){
v.push_back(x);
}
random_shuffle(v.begin(),v.end(),ran);
int need=30;
if(n<=50) need=25;
for(int x=0;x<need;x++){
int hold=kth(v[x]);
int hold2=cnt(hold);
if(hold2*3>n){
say_answer(hold);
return;
}
}
say_answer(-1);
}
