#include "grader.h"
#include <bits/stdc++.h>
using namespace std;
vector <int> e;
vector < vector <int> > g;
void dfs(int u, int p){
e.push_back(u);
for(auto v:g[u]) if(v!=p) dfs(v,u);
}
int findEgg(int N, vector <pair <int,int> > bridges){
g.resize(N+1);
for(auto [u,v]:bridges){
g[u].push_back(v);
g[v].push_back(u);
}
dfs(1,0);
int l=1,r=N,ans=0;
while(l<=r){
int mid=(l+r)>>1;
vector <int> cur;
for(int i=0; i<mid; i++) cur.push_back(e[i]);
if(query(cur)) ans=mid,r=mid-1;
else l=mid+1;
vector <int> ().swap(cur);
}
return e[ans-1];
}
