// Om Namah Shivaya
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)
template<typename T>
void amin(T &a, T b) {
a = min(a, b);
}
template<typename T>
void amax(T &a, T b) {
a = max(a, b);
}
#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif
/*
refs:
edi
*/
const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
#include "highway.h"
void find_pair(int n, std::vector<int> U, std::vector<int> V, int A, int B) {
int m = sz(U);
assert(m == n-1);
vector<pii> adj[n];
rep(i,n-1){
int u = U[i], v = V[i];
adj[u].pb({v,i}), adj[v].pb({u,i});
}
vector<pii> order;
queue<int> q;
q.push(0);
vector<bool> vis(n);
vis[0] = 1;
while(!q.empty()){
int u = q.front();
q.pop();
for(auto [v,id] : adj[u]){
if(vis[v]) conts;
q.push(v);
vis[v] = 1;
order.pb({v,id});
}
}
int l = 0, r = n-2;
int ans = -1;
ll original = 0;
{
vector<int> all_zero(n-1);
original = ask(all_zero);
}
while(l <= r){
// does t lie in order[0..mid]?
int mid = (l+r) >> 1;
vector<int> a(n-1);
for(int i = mid + 1; i < sz(order); ++i){
int id = order[i].ss;
a[id] = 1;
}
ll res = ask(a);
if(res == original){
ans = order[mid].ff;
r = mid - 1;
}
else{
l = mid + 1;
}
}
answer(0,ans);
}
