#include "highway.h"
#include<bits/stdc++.h>
using namespace std;
#define in insert
#define all(x) x.begin(),x.end()
#define pb push_back
#define eb emplace_back
#define ff first
#define ss second
// #define int long long
typedef long long ll;
typedef vector<int> vi;
typedef set<int> si;
typedef multiset<int> msi;
typedef pair<int, int> pii;
typedef vector<pii> vpii;
const int mxn = 1e5 + 10;
int id[mxn], par[mxn], sz;
vector<int> l1, l2, ver[mxn];
vector<pair<int, int>> g[mxn];
void dfs(int to, int fr, int now) {
sz = max(sz, now);
ver[now].pb(to);
par[to] = fr;
for(auto it : g[to]) {
if(it.ff == fr) continue;
id[it.ff] = it.ss;
dfs(it.ff, to, now + 1);
}
}
void find_pair(int n, vector<int> u, vector<int> v, int A, int B) {
int m = u.size();
for(int i = 0; i < m; i++) {
g[u[i]].eb(v[i], i);
g[v[i]].eb(u[i], i);
}
vector<int> q(m, 1);
dfs(0, -1, 0);
long long tot = ask(q);
int dis = tot / B;
int L = 0, R = sz + 1;
while(R - L > 1) {
int M = (L + R) / 2;
q = vector<int>(m, 1);
for(int i = 1; i <= M; i++) {
for(int x : ver[i]) {
q[id[x]] = 0;
}
}
long long ans = ask(q);
if(ans == tot) L = M;
else R = M;
}
int D = L;
L = -1, R = sz;
while(R - L > 1) {
int M = (L + R) / 2;
q = vector<int>(m, 1);
for(int i = sz; i > M; i--) {
for(int x : ver[i]) {
q[id[x]] = 0;
}
}
long long ans = ask(q);
if(ans == tot) R = M;
else L = M;
}
int U = R;
int ans1 = -1, ans2 = -1;
L = 0, R = (int)ver[U].size() - 1;
while(L < R) {
int M = (L + R) / 2;
q = vector<int>(m, 1);
for(int i = 0; i <= M; i++) {
q[id[ver[U][i]]] = 0;
}
long long ans = ask(q);
if(ans == tot) L = M + 1;
else R = M;
}
ans1 = ver[U][L];
if(U - D == dis) {
ans2 = ans1;
for(int i = 0; i < dis; i++) {
ans2 = par[ans2];
}
} else {
int MID = D + dis - (U - D);
reverse(all(ver[MID]));
L = 0, R = (int)ver[MID].size() - 1;
while(L < R) {
int M = (L + R) / 2;
q = vector<int>(m, 1);
for(int i = 0; i <= M; i++) {
q[id[ver[MID][i]]] = 0;
}
long long ans = ask(q);
if(ans == tot) L = M + 1;
else R = M;
}
ans2 = ver[MID][L];
}
answer(ans1, ans2);
// answer(0, 1);
}
