#include "grader.h"
#include <bits/stdc++.h>
using namespace std;
#define EmiliaMyWife ios::sync_with_stdio(0); cin.tie(0);
using ll = int64_t;
using ull = uint64_t;
using uint = uint32_t;
using ld = long double;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
const ll LINF = ll(2e18) + ll(1e15);
const double EPS = 1e-8;
void solve(int n) {
if(n <= 50) {
map<int, int> cnt;
for(int i = 0; i < n; i++) {
cnt[kth(i + 1)]++;
}
for(const auto &[a, b] : cnt)
if(b > n / 3)
return say_answer(a), void();
say_answer(-1);
return;
}
vector<int> arr(n);
for(int i = 0; i < n; i++)
arr[i] = i + 1;
shuffle(arr.begin(), arr.end(), mt19937(time(0)));
set<int> has;
int tmp = 0;
for(int a : arr) {
int x = kth(a);
tmp++;
if(tmp == 60)
break;
if(has.count(x))
continue;
has.insert(x);
int w = cnt(x);
tmp++;
if(w > n / 3) {
say_answer(x);
return;
}
if(tmp == 60)
break;
}
say_answer(-1);
}
