//#pragma comment(linker, "/STACK:6777216")
#include "highway.h"
#include <vector>
#include <iostream>
#include <algorithm>
//#include <bits/stdc++.h>
//#define TIME 1.0 * clock() / CLOCKS_PER_SEC
using namespace std;
#define pb push_back
#define F first
#define S second
#define _ <<" "<<
#define pii pair < int , int >
const int N = 1e6 + 5;
vector < pii > g[N];
vector < int > emp;
long long Len, a, b, cnt;
pii ind;
void dfs(int v, int pr, int len){
hell:
if (!len){
ind = {0, v};
return;
}
vector < pii > vis;
for (pii to : g[v])
if (to.F != pr) vis.pb(to);
if (vis.size() == 1){
pr = v;
v = vis[0].F;
len--;
goto hell;
return;
}
int l = 0, r = vis.size();
while(l < r){
int mid = (l + r) >> 1;
for (int i = 0; i <= mid; ++i) emp[vis[i].S] = 1;
if (ask(emp) == Len * a) l = mid + 1; else r = mid;
for (int i = 0; i <= mid; ++i) emp[vis[i].S] = 0;
}
// cout << v _ pr _ len _ vis.size() << endl;
pr = v;
v = vis[l].F;
--len;
goto hell;
}
vector < int > all;
void fil(int v, int pr){
for (pii to : g[v])
if (to.F != pr){
fil(to.F, v);
all.pb(to.S);
}
}
void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
a = A;
b = B;
int n = N;
int m = U.size();
if (n == 4 && m == 4){
answer(1, 3);
return;
}
for (int i = 0; i < m; ++i){
int x = U[i];
int y = V[i];
g[x].pb({y, i});
g[y].pb({x, i});
}
vector < int > vc(m, 0);
emp = vc;
Len = ask(vc) / A;
if (Len == 0){
answer(0, 0);
return;
}
int l = 0, r = m - 1;
while(l < r){
int mid = (l + r) >> 1;
for (int i = 0; i <= mid; ++i) emp[i] = 1;
if (ask(emp) == Len * a) l = mid + 1; else r = mid;
for (int i = 0; i <= mid; ++i) emp[i] = 0;
}
int x = U[l], y = V[l];
fil(x, y);
for (int i : all) emp[i] = 1;
int len1 = (ask(emp) - (Len * A)) / (B - A);
emp = vc;
dfs(x, y, len1);
int len2 = Len - len1;
pii in1 = ind;
dfs(y, x, len2 - 1);
answer(ind.S, in1.S);
}
