#include <iostream>
#include <vector>
#include "highway.h"
#define int long long
using namespace std;
vector<vector<pair<int, int>>> cons;
vector<signed> w;
void dfs(int i, int from, int d, vector<vector<pair<int, int>>>& put){
for(pair<int, int> p : cons[i]){
int c = p.first, m = p.second;
if(c == from) continue;
put[d+1].push_back({c, m});
w[m] = 1;
dfs(c, i, d+1, put);
}
}
void find_pair(signed N, vector<signed> U, vector<signed> V, signed A, signed B) {
int M = U.size();
cons = vector<vector<pair<int, int>>> (N);
for(int m = 0; m < M; m++){
cons[U[m]].push_back({V[m], m});
cons[V[m]].push_back({U[m], m});
}
int dst = ask(vector<signed> (M))/(int)A;
auto qrange = [&](int ll, int rl){
vector<signed> wl(M);
for(int i = ll; i < rl; i++) wl[i] = 1;
return ask(wl) != dst*(int)A;
};
int l = 0, r = M;
while(l + 1 < r){
int m = l + (r-l)/2;
if(qrange(l, m)) r = m;
else l = m;
}
vector<vector<pair<int, int>>> side1 (N);
vector<vector<pair<int, int>>> side2 (N);
w = vector<signed>(M);
dfs(U[l], V[l], 0, side1);
w = vector<signed>(M);
dfs(V[l], U[l], 0, side2);
int dst2 = (ask(w)-dst*(int)A)/(int)(B-A);
auto bs_sel = [&](vector<pair<int, int>> sel){
int l = 0, r = sel.size();
while(l + 1 < r){
int m = l + (r-l)/2;
vector<signed> lw (M);
for(int set = l; set < m; set++) lw[sel[set].second] = 1;
if(ask(lw) != dst*(int)A) r = m;
else l = m;
}
return sel[l].first;
};
int u, s;
if(dst2 > 0) u = bs_sel(side2[dst2]);
else u = V[l];
if(dst-dst2-1 > 0) s = bs_sel(side1[dst-dst2-1]);
else s = U[l];
answer(u, s);
}
