#//include "grader.cpp"
#include <bits/stdc++.h>
#include "grader.h"
using namespace std;
#define pb push_back
#define mp make_pair
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
int n;
vi G[550], euler;
void dfs(int at, int p){
euler.pb(at);
for(auto next : G[at]){
if(next == p) continue;
dfs(next, at);
euler.pb(at);
}
}
int findEgg (int N, vector < pair < int, int > > bridges)
{
n = N;
for(int i = 0; i < n; i++) G[i].clear();
for(auto t : bridges){
G[t.first].pb(t.second);
G[t.second].pb(t.first);
}
euler.clear();
dfs(1, 0);
int l = 0, r = (int)euler.size()-1, ans = -1;
while(r-l>=1){
int mid = (l + r) / 2;
set<int> ask;
for(int i = l; i <= mid; i++){
ask.insert(euler[i]);
}
vi is;
for(auto t : ask) is.pb(t);
int s = query(is);
if(s == 1){
ans = mid;
r = mid;
}
else{
l = mid+1;
}
}
return euler[ans];
}
