#include <bits/stdc++.h>
#include "grader.h"
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define ALL(v) (v).begin(), (v).end()
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
// mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng(1);
ll rngesus(ll l, ll r){return ((ull) rng()) % (r - l + 1) + l;}
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll LASTBIT(ll mask){return mask & (-mask);}
ll pop_cnt(ll mask){return __builtin_popcountll(mask);}
ll ctz(ll mask){return __builtin_ctzll(mask);}
ll clz(ll mask){return __builtin_clzll(mask);}
ll logOf(ll mask){return 63 - clz(mask);}
template <class T1, class T2>
bool minimize(T1 &a, T2 b){
if (a > b){a = b; return true;}
return false;
}
template <class T1, class T2>
bool maximize(T1 &a, T2 b){
if (a < b){a = b; return true;}
return false;
}
template <class T>
void printArr(T& a, string separator = " ", string finish = "\n", ostream& out = cout){
for(auto i: a) out << i << separator;
out << finish;
}
template <class T>
void remove_dup(vector<T> &a){
sort(ALL(a));
a.resize(unique(ALL(a)) - a.begin());
}
void solve(int n){
if (n <= 60){
map<int, int> mp;
for(int i = 1; i<=n; ++i) mp[kth(i)]++;
for(pair<int, int> i: mp){
if (i.second > n / 3) {
say_answer(i.first);
return;
}
}
}
else{
set<int> S;
vector<int> perm(n);
for(int i= 0; i<n; ++i)perm[i] = i + 1;
shuffle(ALL(perm), rng);
for(int j= 0, i = 0;j <= 58;++i){
int x = kth(perm[i]); j++;
if (S.find(x) == S.end()){
int y = cnt(x);
if (y > n / 3) {
say_answer(x);
return;
}
j++;
}
}
}
say_answer(-1);
}
// int main(void){
// ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
// // double rate = 1;
// // for(int i = 0; i<30; ++i) rate = rate * 2 / 3;
// // double sigma = 1 - rate;
// // rate = 1;
// // for(int i = 0; i<16000; ++i) rate = rate * sigma;
// // cout << fixed << setprecision(10) << rate << "\n";
// return 0;
// }
