#include "highway.h"
//#include "grader.cpp"
#include <bits/stdc++.h>
#define pii pair<int, int>
#define fr first
#define sc second
#define szof(s) (int)s.size()
#define all(s) s.begin(), s.end()
#define mk make_pair
#define pb push_back
#define ll long long
using namespace std;
const int MAXN = 130005;
const int INF = 0x3f3f3f3f;
ll from[MAXN], to[MAXN];
vector <ll> g[MAXN];
ll dist[MAXN];
ll pr[MAXN];
ll costa, costb;
ll min_path;
ll diametr;
ll n, m;
ll Q;
map <pii, ll> id;
void make_edge(ll x, ll y) {
g[x].pb(y);
g[y].pb(x);
}
ll find_middle_edge() {
ll l = 0, r = m - 1;
vector <int> w(m);
while (l != r) {
ll mid = (l + r) >> 1;
for (ll i = l; i <= r; i++) {
if (i <= mid) {
w[i] = 1;
} else {
w[i] = 0;
}
}
ll cur_cost = ask(w);
Q++;
if (cur_cost != min_path) {
r = mid;
} else {
l = mid + 1;
}
}
return l;
}
ll get_min_path() {
vector <int> w(m);
for (int i = 0; i < m; i++) {
w[i] = 0;
}
ll cur_cost = ask(w);
Q++;
return cur_cost;
}
void dfs(ll v, ll par, ll len, vector <ll> &s_sub) {
for (int to : g[v]) {
if (to != par) {
s_sub.pb(id[{v, to}]);
dfs(to, v, len + 1, s_sub);
}
}
}
void calc_dist_and_pr(int v, int par, int len) {
dist[v] = len;
pr[v] = par;
for (int to : g[v]) {
if (to != par) {
calc_dist_and_pr(to, v, len + 1);
}
}
}
int find_s(vector <ll> s_sub) {
vector <int> w(m, 0);
for (ll el : s_sub) {
w[el] = 1;
}
ll cost = ask(w);
Q++;
ll root_to_s = (cost - min_path) / (costb - costa);
vector <int> possible;
for (int i = 0; i < n; i++) {
if (dist[i] == root_to_s) {
possible.pb(id[{i, pr[i]}]);
}
}
ll l = 0, r = szof(possible) - 1;
while (l != r) {
ll mid = (l + r) >> 1;
for (ll i = 0; i < m; i++) {
w[i] = 0;
}
for (ll i = l; i <= mid; i++) {
w[possible[i]] = 1;
}
ll cur_cost = ask(w);
Q++;
if (cur_cost != min_path) {
r = mid;
} else {
l = mid + 1;
}
}
ll need_edge = possible[l];
if (dist[from[need_edge]] == root_to_s) {
return from[need_edge];
} else {
return to[need_edge];
}
}
void find_pair(int N, vector<int> U, vector<int> V, int AA, int BB) {
costa = AA, costb = BB;
m = U.size();
n = N;
for (ll i = 0; i < m; i++) {
from[i] = U[i];
to[i] = V[i];
id[{from[i], to[i]}] = i;
id[{to[i], from[i]}] = i;
make_edge(from[i], to[i]);
}
min_path = get_min_path();
diametr = min_path / costa;
ll mid_edge = find_middle_edge();
ll root = from[mid_edge];
ll need_sub = to[mid_edge];
vector <ll> s_sub;
s_sub.pb(id[{root, need_sub}]);
memset(dist, -1, sizeof(dist));
calc_dist_and_pr(need_sub, root, 1);
dist[root] = 0;
dfs(need_sub, root, 1, s_sub);
ll SS = find_s(s_sub);
memset(dist, -1, sizeof(dist));
calc_dist_and_pr(SS, -1, 0);
vector <ll> possible;
for (ll i = 0; i < n; i++) {
if (dist[i] == diametr) {
possible.pb(id[{i, pr[i]}]);
}
}
ll l = 0, r = szof(possible) - 1;
vector <int> w(m);
while (l != r) {
ll mid = (l + r) >> 1;
for (ll i = 0; i < m; i++) {
w[i] = 0;
}
for (ll i = l; i <= mid; i++) {
w[possible[i]] = 1;
}
ll cur_cost = ask(w);
Q++;
if (cur_cost != min_path) {
r = mid;
} else {
l = mid + 1;
}
}
ll need_edge = possible[l];
ll TT;
if (dist[from[need_edge]] == diametr) {
TT = from[need_edge];
} else {
TT = to[need_edge];
}
if (SS > TT) {
swap(SS, TT);
}
answer(SS, TT);
}
