#include "highway.h"
#include <bits/stdc++.h>
#define debug printf
#define lp(i,a,b) for(int i=a;i<b;i++)
#define pii pair<int,int>
#define ll long long
#define ff first
#define ss second
#define pb push_back
#define mk make_pair
const int MAXN = 9e4+ 10 ;
const int MAXM = 13e4+10 ;
using namespace std ;
struct Edge
{
int j , id ;
Edge(int j = 0 , int id = 0)
: j(j) , id(id) {}
} ;
int n , m , S , T ;
int edgePai[MAXN] ;
vector<int> toAsk , possible ;
ll rad , Prev ;
vector<Edge> adj[MAXN] ;
bool marc[MAXN] ;
// --------------------------------
void prepareDfs()
{
memset(marc,false, sizeof marc) ;
possible.resize(0) ;
}
void dfs(int x , ll depth , ll curRad , bool allowed[])
{
if( depth == curRad ) possible.pb(x) ;
marc[x] = true ;
for( Edge e : adj[x] )
if( !marc[e.j] && allowed[e.id] )
{
edgePai[e.j] = e.id ;
dfs( e.j , depth+1, curRad , allowed ) ;
}
}
int findSpecial(int s , bool allowed[] , ll curRad )
{
prepareDfs() ;
dfs(s , 0 , curRad , allowed) ;
int l = 0 , r = possible.size() - 1 , mid , best=0 ;
while( l <= r )
{
mid = (l+r)/2 ;
lp(i,l,mid+1) toAsk[ edgePai[ possible[i] ] ] = 1 ;
ll newTot = ask(toAsk) ;
lp(i,l,mid+1) toAsk[ edgePai[ possible[i] ] ] = 0 ;
if( newTot > Prev )
{
r = mid - 1 ;
best = mid ;
}
else l = mid+1 ;
}
return possible[best] ;
}
bool allowed[MAXM] ;
void find_pair(int N, vector<int> U, vector<int> V, int A, int B) {
m = U.size();
n = N ;
lp(i,0,m)
{
int a = U[i] , b = V[i] ;
adj[a].pb(Edge(b,i)) ;
adj[b].pb(Edge(a,i)) ;
toAsk.pb(0) ;
allowed[i] = 1 ;
}
Prev = ask(toAsk) ;
rad = Prev/A ;
T = findSpecial(0 , allowed , rad) ;
answer(S,T) ;
}
