//Sylwia Sapkowska
#include <bits/stdc++.h>
#include "chameleon.h"
#pragma GCC optimize("O3")
#pragma GCC target ("avx2")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("unroll-loops")
using namespace std;
void __print(int x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
void Solve(int n){
int N = 2*n;
vector<vector<int>>G(N+1);
vector<int>c(N+1);
function<bool(vector<int>, int)>check = [&](vector<int>a, int x){
if (a.empty()) return false;
a.emplace_back(x);
return (Query(a) != (int)a.size());
};
for (int i = 1; i<=N; i++){
for (int j = 1; j<i; j++) c[j] = -1;
for (int j = 1; j<i; j++){
if (c[j] != -1) continue;
queue<int>q;
q.push(j);
c[j] = 0;
while (q.size()){
int v = q.front();q.pop();
for (auto x: G[v]){
if (c[x] == -1){
c[x] = c[v]^1;
q.push(x);
}
}
}
}
vector<vector<int>>d(2);
for (int j = 1; j<i; j++) d[c[j]].emplace_back(j);
for (int j = 0; j<2; j++){
while (check(d[j], i)){
int L = 0, R = (int)d[j].size()-1;
int ans = R;
while (R>=L){
int m = (L+R)/2;
vector<int>x;
for (int k = 0; k<=m; k++) x.emplace_back(d[j][k]);
if (check(x, i)){
ans = m;
R = m-1;
} else L = m+1;
}
// debug(i, ans);
G[i].emplace_back(d[j][ans]);
G[d[j][ans]].emplace_back(i);
d[j].erase(d[j].begin(), d[j].begin()+ans+1);
}
}
}
// for (int i = 1; i<=N; i++){
// debug(G[i]);
// }
vector<pair<int, int>>ans;
vector<int>who2(N+1, -1), who(N+1, -1);
vector<bool>vis(N+1, 0);
for (int i = 1; i<=N; i++){
if ((int)G[i].size() == 1 && !vis[G[i][0]]){
ans.emplace_back(i, G[i][0]);
vis[i] = 1;
vis[G[i][0]] = 1;
} else if (G[i].size() == 3) {
vector<int>curr;
for (int j = 0; j<3; j++){
curr.clear();
for (int k = 0; k<3; k++){
if (k == j) continue;
curr.emplace_back(G[i][k]);
}
curr.emplace_back(i);
if (Query(curr) == 1){
who2[i] = G[i][j];
who[G[i][j]] = i;
}
}
}
}
for (int i = 1; i<=N; i++){
if (vis[i]) continue;
if ((int)G[i].size() == 3){
for (int j = 0; j<3; j++){
if (G[i][j] == who2[i] || G[i][j] == who[i]) continue;
ans.emplace_back(i, G[i][j]);
vis[i] = 1;
vis[G[i][j]] = 1;
}
}
}
for (auto [a, b]:ans) Answer(a, b);
}
