#include "highway.h"
#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define vi vector<int>
#define ff first
#define all(x) x.begin(),x.end()
#define ss second
#define ll long long int
#define pii pair<int,int>
const int N = 2e5+100;
int s[N], dep[N], PAR[N];
vector<pii> g[N];
bitset<N> VIS;
void find_pair(int n, std::vector<int> U, std::vector<int> V, int A, int B) {
int m = U.size();
for(int i = 0; i < m; ++i){
g[U[i]].pb({V[i], i});
g[V[i]].pb({U[i], i});
}
vi w(m);
ll val = ask(w);
int k = val / A;
int l = 0, r = m - 2, res = m-1;
while(l <= r){
int mid = l+r>>1;
w.clear();
w.resize(m);
for(int j = 0; j <= mid; ++j) w[j] = 1;
ll y = ask(w);
if(y != val){
res = mid;
r = mid - 1;
}else{
l = mid + 1;
}
}
int x = U[res];
int y = V[res];
queue<int> q;
q.push(x);
vector<int> D(n, -1);
vector<int> D1(n, -1);
vi par1(n, -1);
vi par2(n, -1);
D[x] = 0;
while(!q.empty()){
int v = q.front();
q.pop();
for(auto [u, id]: g[v]){
if(D[u] == -1){
D[u] = D[v] + 1;
par1[u] = id;
q.push(u);
}
}
}
q.push(y);
D1[y] = 0;
while(!q.empty()){
int v = q.front();
q.pop();
for(auto [u, id]: g[v]){
if(D1[u] == -1){
D1[u] = D1[v] + 1;
par2[u] = id;
q.push(u);
}
}
}
vector<pii> X, Y;
for(int i = 0; i < n; ++i){
if(D[i] < D1[i]) X.pb({D[i], i});
else if(D1[i] < D[i]) Y.pb({D1[i], i});
}
sort(all(X));
int ress = res;
l = 0, r = int(X.size()) - 1, res = 0;
while(l <= r){
int mid = l+r>>1;
w.clear();
w.resize(m, 1);
for(auto [d, v]: Y) if(par2[v] != -1) w[par2[v]] = 0;
w[ress] = 0;
for(int i = 0; i <= mid; ++i) if(par1[X[i].ss] != -1) w[par1[X[i].ss]] = 0;
ll y = ask(w);
if(y == val){
res = mid;
r = mid - 1;
}else{
l = mid + 1;
}
}
int s = X[res].ss;
sort(all(Y));
l = 0, r = int(Y.size()) - 1, res = 0;
while(l <= r){
int mid = l+r>>1;
w.clear();
w.resize(m, 1);
for(auto [d, v]: X) if(par1[v] != -1) w[par1[v]] = 0;
w[ress] = 0;
for(int i = 0; i <= mid; ++i) if(par2[Y[i].ss] != -1) w[par2[Y[i].ss]] = 0;
ll y = ask(w);
if(y == val){
res = mid;
r = mid - 1;
}else{
l = mid + 1;
}
}
int t = Y[res].ss;
// cerr << s << ' ' << t << '\n';
answer(s, t);
}
