#include <bits/stdc++.h>
#include "grader.h"
using namespace std;
int i, j, l, r, mid, p, q, k, t, n, m, a, b, c, d, ans, cnt, res, cor[200005], tin[200005];
const long long mod = 999993143, mod2 = 999993469;
string s;
bool check;
vector <int> adj[200005], qq;
void dfs (int u, int v){
t += 1;
int i, p;
tin[u] = t;
for (i = 0; i < adj[u].size(); i += 1){
p = adj[u][i];
if (p != v){
dfs(p, u);
}
}
}
int findEgg (int N, vector <pair <int, int> > bridges){
n = N;
for (i = 0; i < n - 1; i += 1){
a = bridges[i].first;
b = bridges[i].second;
adj[a].push_back(b);
adj[b].push_back(a);
}
t = 0;
dfs(1, -1);
for (i = 1; i <= n; i += 1){
cor[tin[i]] = i;
}
l = 1;
r = n;
ans = -1;
// while (l <= r){
// mid = (l + r) / 2;
// qq.clear();
// for (i = 1; i <= mid; i += 1){
// qq.push_back(cor[i]);
// }
// res = query(qq);
// if (res == 1){
// ans = cor[mid];
// r = mid - 1;
// }
// else{
// l = mid + 1;
// }
// }
return ans;
}
