#include "highway.h"
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int maxn = 2e5 + 10;
typedef pair<int,int> ii;
#define ff first
#define ss second
int n,m;
ll dist,w1,w2,dist2;
vector <ii> adj[maxn];
ii e[maxn];
int d[maxn]; ii par[maxn];
int side[maxn];
int dnc(int lx, int rx, vector<int32_t> &dau)
{
if (lx==rx) return lx;
int mid=(lx+rx)/2;
for (int i=lx; i<=mid; i++) dau[i] = 0;
ll temp = ask(dau);
// for (int i:dau) cerr<<i<<' '; cerr<<" = "<<temp<<'\n';
bool check = temp < dist2;
for (int i=lx; i<=mid; i++) dau[i] = 1;
if (check) return dnc(lx,mid,dau);
else return dnc(mid+1,rx,dau);
}
int trace(int lx, int rx, vector <int>&nodes, vector <int32_t> &dau)
{
if (lx==rx) return nodes[lx];
int mid=(lx+rx)/2;
for (int i=lx; i<=mid; i++) dau[par[nodes[i]].ss] = 1;
bool check = (ask(dau) > dist);
for (int i=lx; i<=mid; i++) dau[par[nodes[i]].ss] = 0;
if (check) return trace(lx,mid,nodes,dau);
else return trace(mid+1,rx,nodes,dau);
}
void find_pair(int N, std::vector<int> U, std::vector<int> V, int A, int B) {
m=U.size(); n=N; w1=A; w2=B;
fill_n(side,n,0);
for (int i=0; i<n; i++) par[i]={-1,-1};
// cerr<<":>"<<endl;
for (int i=0; i<n; i++) adj[i].clear();
for (int i=0; i<m; i++) e[i].ff=U[i], e[i].ss = V[i], adj[e[i].ff].push_back({e[i].ss,i}), adj[e[i].ss].push_back({e[i].ff,i});
vector <int32_t> dau(m,0);
dist=ask(dau);
for (int i=0; i<m; i++) dau[i]=1;
dist2=ask(dau);
cerr<<dist<<endl;
int idx = dnc(0,m-1,dau);
for (int i=0; i<m; i++) dau[i]=0;
cerr<<idx<<endl;
fill_n(d,n,-1);
int u=e[idx].ff; int v=e[idx].ss;
d[u]=d[v]=0; par[u] = par[v] = {-1,-1};
dau[idx] = -1;
queue<int> q;
q.push(u); q.push(v);
side[u] = 1; side[v] = 2;
while (!q.empty())
{
int u=q.front(); q.pop();
for (ii i:adj[u])
{
int v=i.ff; int id = i.ss;
if (d[v]==-1)
{
par[v] = {u,id};
side[v] = side[u];
d[v] = d[u]+1;
cerr<<u<<" - "<<v<<endl;
dau[id] = side[v];
q.push(v);
}
}
}
vector <int32_t> tmp(m,0);
for (int i=0; i<m; i++) if (dau[i]==0) tmp[i]=1;
for (int i=0; i<m; i++) if (dau[i]==1) tmp[i]=1;
for (int i:tmp) cerr<<i<<' '; cerr<<endl;cerr<<" = "<<ask(tmp)<<' '<<dist<<endl;
ll du = 1LL*(ask(tmp)-dist)/(w2-w1);
for (int i=0; i<m; i++) if (dau[i]==1) tmp[i]=0;
for (int i=0; i<m; i++) if (dau[i]==2) tmp[i]=1;
ll dv = 1LL*(ask(tmp)-dist)/(w2-w1);
for (int i=0; i<m; i++) if (dau[i]==2) tmp[i]=0;
cerr<<u<<' '<<du<<" & "<<v<<' '<<dv<<endl;
vector <int> nodes;
for (int i=0; i<n; i++) if (side[i]==1&&d[i]==du) nodes.push_back(i);
// for (int i=0; i<n; i++) cerr<<d[i]<<','<<side[i]<<' '; cerr<<endl;
int s,t;
// cerr<<nodes.size()<<endl;
if (du==0) s=u;
else s=trace(0,nodes.size()-1,nodes,tmp);
nodes.clear();
for (int i=0; i<n; i++) if (side[i]==2&&d[i]==dv) nodes.push_back(i);
if (dv==0) t=v;
else t=trace(0,nodes.size()-1,nodes,tmp);
answer(s,t);
}
