//#include "grader.h"
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <vector>
#include <math.h>
#include <set>
//#define int long long
#define ff first
#define ss second
#define pb push_back
#define pp pop_back
#define all(x) x.begin(),x.end()
#define pii pair<int,int>
#define r0 return 0
using namespace std;
const int N = 5 * 1e5 + 5, M = 55, MOD = 998244353;
int x,y,xx,yy,n,m,k,l,ans,tm,check = 0;
vector <int> g[N],rd,v;
int fix[N],tc[N];
int kth(int i);
int cnt(int x);
void say_answer(int a);
void solve(int N){
n = N;
srand(time(0) ^ clock());
for (int i = 1; i <= 30; i++) {
int ind = rand() % n + 1;
int pick = kth(ind);
if (cnt(pick) > n / 3 and check == 0) {
say_answer(pick);
break; check = 1;
}
}
if (check = 0) say_answer(-1);
}
