#include <bits/stdc++.h>
#include "grader.h"
/*#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>*/
#define ll long long
#define ll1 long long
#define ull unsigned long long
#define dou long double
#define str string
#define vll vector<ll>
#define vi vector<int>
#define pll pair<ll, ll>
#define vpll vector<pll>
#define vbool vector<bool>
#define vstr vector<str>
#define vvll vector<vll>
#define pb push_back
#define pf push_front
//#define endl "\n"
#define fr first
#define se second
// #define sortcmp(a) sort(a.begin(), a.end(), cmp)
#define sort(a) sort(a.begin(), a.end())
#define reverse(a) reverse(a.begin(), a.end())
#define speed ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define INF 5000000000000000000
#define ordered_set tree<ll, null_type, less_equal<ll>, rb_tree_tag, tree_order_statistics_node_update>
using namespace std;
//using namespace __gnu_pbds;
mt19937 rng(time(0));
ll randll(ll l, ll r){
return uniform_int_distribution<ll>(l, r)(rng);
}
vbool us;
vector<int> c;
vvll g;
ll k1 = 0;
ll x;
void dfs(ll v, ll k, ll p = -1) {
c.pb(v);
if (!us[v]) k1 ++;
if (k1 == k) return;
for (int i : g[v]) {
if (i == p) continue;
dfs(i, k, v);
if (k1 == k) return;
}
}
/*int query(vector < int > islands) {
for (int i : islands) {
if (i == x) return 1;
}
return 0;
}*/
int findEgg(int n, vector < pair < int, int > > bridges) {
vll a;
us.clear();
us.resize(n+7, 0);
//vbool us1(n+7, 1);
g.clear();
g.resize(n+7);
for (int i = 1; i <= n; i ++) {
a.pb(i);
}
for (auto i : bridges) {
g[i.fr].pb(i.se);
g[i.se].pb(i.fr);
}
while (a.size() > 1) {
c.clear();
k1 = 0;
dfs(a[0], a.size()/2);
vector<int> c1 = c;
if (query(c1)) {
set<ll> s;
vll b;
for (int i : c) {
if (!us[i]) {
s.insert(i);
b.pb(i);
}
}
for (int i : a) {
if (s.find(i) == s.end()) us[i] = 1;
}
a = b;
}
else {
vll b;
for (int i : c) {
us[i] = 1;
}
for (int i : a) {
if (!us[i]) b.pb(i);
}
a = b;
}
}
if (a.empty()) return 1;
return a[0];
}
/*int main() {
ll n;
cin >> n >> x;
vector<pair<int, int>> v;
for (int i = 0; i < n-1; i ++) {
ll a, b;
cin >> a >> b;
v.pb({a, b});
}
cout << findEgg(n, v) << endl;
}*/
