#include "highway.h"
#include <bits/stdc++.h>
#define ff first
#define ss second
using namespace std;
typedef pair<int, int> pii;
vector<int> sor;
vector<int> cnd;
const int MAXN = (int) 9e4 + 5;
vector<pii> adj[MAXN];
int open[MAXN];
int dep[MAXN];
long long der;
void dfs(int v, int par){
if(dep[v] == der) {cnd.push_back(v); return;}
for(pii u: adj[v]){
int j = u.ff;
if(j != par){
dep[j] = dep[v] + 1;
dfs(j, v);
}
}
}
bool dfs1(int v, int par){
if(open[v]) return 1;
bool vardi = 0;
for(pii u: adj[v]){
if(u.ff == par) continue;
bool var = dfs1(u.ff, v);
vardi |= var;
if(var){
sor[u.ss] = 0;
}
}
return vardi;
}
void find_pair(int N, vector<int> U, vector<int> V, int A, int B) {
int M = U.size();
int s = 0, t;
for(int i = 0; i < M; i++) {
sor.push_back(0);
adj[U[i]].push_back({V[i], i});
adj[V[i]].push_back({U[i], i});
}
der = ask(sor) / A;
dfs(0, -1);
int l = 0, r = cnd.size() - 1;
while(l < r){
int m = (l + r) / 2;
for(int i = 0; i < M; i++) sor[i] = 1;
for(int i = l; i <= m; i++){
open[cnd[i]] = 1;
}
dfs1(0, -1);
for(int i = l; i <= m; i++){
open[cnd[i]] = 0;
}
long long dr = ask(sor);
if(dr == der*A){
r = m;
}else{
l = m + 1;
}
}
t = cnd[l];
answer(s,t);
}
