#include "highway.h"
#include <bits/stdc++.h>
#include <bits/extc++.h>
#define StarBurstStream ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define iter(a) a.begin(), a.end()
#define riter(a) a.rbegin(), a.rend()
#define lsort(a) sort(iter(a))
#define gsort(a) sort(riter(a))
#define pb(a) push_back(a)
#define eb(a) emplace_back(a)
#define pf(a) push_front(a)
#define ef(a) emplace_front(a)
#define pob pop_back()
#define pof pop_front()
#define mp(a, b) make_pair(a, b)
#define F first
#define S second
#define mt make_tuple
#define gt(t, i) get<i>(t)
#define tomax(a, b) ((a) = max((a), (b)))
#define tomin(a, b) ((a) = min((a), (b)))
#define topos(a) ((a) = (((a) % MOD + MOD) % MOD))
#define uni(a) a.resize(unique(iter(a)) - a.begin())
#define printv(a, b) {bool pvaspace=false; \
for(auto pva : a){ \
if(pvaspace) b << " "; pvaspace=true;\
b << pva;\
}\
b << "\n";}
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<ld, ld>;
using tiii = tuple<int, int, int>;
const ll MOD = 1000000007;
const ll MAX = 2147483647;
template<typename A, typename B>
ostream& operator<<(ostream& o, pair<A, B> p){
return o << '(' << p.F << ',' << p.S << ')';
}
ll ifloor(ll a, ll b){
if(b < 0) a *= -1, b *= -1;
if(a < 0) return (a - b + 1) / b;
else return a / b;
}
ll iceil(ll a, ll b){
if(b < 0) a *= -1, b *= -1;
if(a > 0) return (a + b - 1) / b;
else return a / b;
}
int n, m;
#define query ask
//ll query(vector<int> qry){
// ll tmp = ask(qry);
// cerr << "query " << tmp << " ";
// printv(qry, cerr);
// return tmp;
//}
void find_pair(int N, vector<int> U, vector<int> V, int A, int B) {
n = N;
m = U.size();
vector<vector<pii>> g(n);
for(int i = 0; i < m; i++){
int u = U[i], v = V[i];
g[u].eb(mp(v, i));
g[v].eb(mp(u, i));
}
vector<int> qry(m);
ll dis = query(qry);
int l = 0, r = m - 1;
while(l < r){
int mid = (l + r) / 2;
fill(qry.begin() + l, qry.begin() + mid + 1, 1);
// cerr << l << " " << r << " " << mid << "\n";
if(query(qry) != dis){
r = mid;
fill(qry.begin() + l, qry.begin() + mid + 1, 0);
}
else l = mid + 1;
}
int e = l;
int u = U[e], v = V[e];
// cerr << e << " " << u << " " << v << "\n";
auto getdis = [g](int s){
vector<int> d(n, -1);
vector<int> p(n, -1);
queue<int> q;
q.push(s);
d[s] = 0;
while(!q.empty()){
int now = q.front();
q.pop();
for(pii i : g[now]){
if(d[i.F] != -1) continue;
p[i.F] = i.S;
d[i.F] = d[now] + 1;
q.push(i.F);
}
}
return mp(d, p);
};
vector<int> du, pu, dv, pv;
tie(du, pu) = getdis(u);
tie(dv, pv) = getdis(v);
vector<pii> us, vs;
for(int i = 0; i < n; i++){
if(du[i] < dv[i]) us.eb(mp(du[i], i));
else vs.eb(mp(dv[i], i));
}
fill(iter(qry), 1);
for(pii i : us) qry[pu[i.S]] = 0;
for(pii i : vs) qry[pv[i.S]] = 0;
qry[e] = 0;
lsort(us);
lsort(vs);
auto owo = [qry, dis](vector<pii>& s, vector<int>& p){
int l = 0, r = (int)s.size() - 1;
while(l < r){
int mid = (l + r + 1) / 2;
vector<int> tmp = qry;
for(int i = mid; i <= r; i++) tmp[p[s[i].S]] = 1;
// cerr << "test " << l << " " << r << " " << mid << "\n";
if(query(tmp) == dis) r = mid - 1;
else l = mid;
}
return s[l].S;
};
int v1 = owo(us, pu);
int v2 = owo(vs, pv);
// cerr << v1 << " " << v2 << "\n";
answer(v1, v2);
}
