#include "grader.h"
#include <bits/stdc++.h>
using namespace std;
int findEgg (int N, vector<pair<int, int>> edges) {
vector<int> g[N];
for (auto [u, v] : edges) {
-- u; -- v;
g[u].push_back(v);
g[v].push_back(u);
}
vector<int> ord;
function<void(int, int)> dfs = [&](int si, int pi) -> void {
ord.push_back(si);
for (auto ti : g[si]) if (ti != pi) {
dfs(ti, si);
}
};
dfs(0, 0);
int low = 0, high = N - 1, best = 0;
while (low < high) {
int mid = (low + high) / 2;
vector<int> tmp;
for(int i = 0;i <= mid;i ++) tmp.push_back(ord[i]);
if (query(tmp) == 1) {
high = mid;
} else {
low = mid + 1;
}
}
return ord[low] + 1;
}
