#include "highway.h"
#include<bits/stdc++.h>
#define K 1<<17
using namespace std;
int bfspos[2][K],CC,bfspar[2][K],bfspari[2][K],bfsdis[2][K];
vector<pair<int,int>>adj[K];
void bfs(int n,int i){
queue<int>q;
int CC=0;
memset(bfsdis[i],-1,sizeof *bfspos);
q.push(n);
bfsdis[i][n]=0;
bfspar[i][n]=-1;
while(q.size()){
int x=q.front(),d=bfsdis[i][x];
q.pop(); bfspos[i][x]=++CC;
for(auto [j,k]:adj[x]) if(bfsdis[i][j]<0)
bfspar[i][j]=x,bfspari[i][j]=k,
bfsdis[i][j]=d+1,q.push(j);
}
}
int indd;
int whicho(int pivot,int N,int ind,int M,vector<int>v,long long D,int spec){
indd=ind;
sort(v.begin(),v.end(),[](int a,int b){
return bfspos[indd][a]<bfspos[indd][b];
});
int l=1,r=v.size()-1,res=1;
while(l<=r){
int mid=l+r>>1;
vector<int>V(M,1);
V[spec]=0;
for(int i=mid;i<v.size();i++) {
if(bfspar[ind][v[i]]!=pivot)
if(!V[bfspari[ind][bfspar[ind][v[i]]]])
continue;
V[bfspari[ind][v[i]]]=0;
}
if(ask(V)<D)
l=res=mid+1;
else r=mid-1;
}
return v[res-1];
}
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++)
adj[U[i]].push_back({V[i],i}),
adj[V[i]].push_back({U[i],i});
long long D=ask(vector<int>(M,0))/A;
int res=1e9,l=1,r=M-1;
while(l<=r){
int mid=l+r>>1;
vector<int>v(M);
for(int i=0;i<mid;i++)
v[i]=1;
if(ask(v)>D*A)
res=r=mid-1;
else l=mid+1;
}
int a=U[res],b=V[res];
bfs(a,0);
bfs(b,1);
vector<int>sta,stb;
for(int i=0;i<N;i++)
if(bfsdis[0][i]<bfsdis[1][i])
sta.push_back(i);
else if(bfsdis[0][i]-bfsdis[1][i])
stb.push_back(i);
answer(whicho(a,N,0,M,sta,D*B-B+A,res),
whicho(b,N,1,M,stb,D*B-B+A,res));
}
