#include <bits/stdc++.h>
#include "grader.h"
#define all(x) x.begin(), x.end()
#define sz(x) (int) x.size()
#define endl '\n'
#define pb push_back
#define _ ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ii = pair<int,int>;
using iii = tuple<int,int,int>;
const int inf = 2e9+1;
const int mod = 1e9+7;
const int maxn = 3e5+100;
template<typename X, typename Y> bool ckmin(X& x, const Y& y) { return (y < x) ? (x=y,1):0; }
template<typename X, typename Y> bool ckmax(X& x, const Y& y) { return (x < y) ? (x=y,1):0; }
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int findEgg(int n, vector<ii> edg) {
vector<vector<int>> g(n+1);
for (auto [x, y] : edg) g[x].pb(y), g[y].pb(x);
vector<int> in(n+1);
int tt = 0;
auto dfs = [&] (auto&& self, int u, int p) -> void {
in[++tt] = u;
for (auto v : g[u]) {
if (v == p) continue;
self(self, v, u);
}
};
dfs(dfs, 1, 1);
return 1;
int l = 1, r = n, ans = n;
while (l <= r) {
int md = l + (r-l+1)/2;
vector<int> qq;
for (int i = 1; i <= md; ++i) qq.pb(in[i]);
if (query(qq)) ans = md, l = md+1;
else r = md-1;
}
return in[ans];
}
