#include <bits/stdc++.h>
#include "highway.h"
using namespace std;
#define pb push_back
#define ss second
#define ff first
#define sz(a) int(a.size())
#define all(a) a.begin(),a.end()
typedef long double ld;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
const ll inf = 1e18;
const int mod = 1e9+7; //998244353;
const int maxn = 1e5+5;
const int Xg[4] = {1,0,-1,0}, Yg[4] = {0,1,0,-1};
ll modpw(ll a,ll e) {if(e==0)return 1;ll x=modpw(a*a%mod,e>>1);return e&1?x*a%mod:x;}
int M;
vi col,C,D;
ll init;
queue<pii>q;
int dis[maxn];
vector<pii> adj[maxn];
int bin(vi v){
int l = 0,r = sz(v) - 1,md,jog=0;
while(l <= r){
md = (l+r)/2;
for(int i = 0;i < M;i++) col[i]=0;
for(int i = md;i < sz(v);i++)
for(auto j : adj[v[i]]) col[j.ss]=1;
ll now=ask(col);
if(now != init) l=md+1,jog=md;
else r=md-1;
}
return v[jog];
}
void find_pair(int N, vi U, vi V, int A, int B) {
M = sz(U); col.resize(M);
for(int i = 0;i < M;i++){adj[U[i]].pb({V[i],i});adj[V[i]].pb({U[i],i});}
init = ask(col);
int l = 0,r = M-1,md,jog=0;
while(l <= r){
md = (l+r)/2;
for(int i = 0;i <= md;i++) col[i]=1;
for(int i = md+1;i < M;i++) col[i]=0;
ll now=ask(col);
if(now != init) r=md-1,jog=md;
else l=md+1;
}
q.push({U[jog],1}); dis[U[jog]]=1;
q.push({V[jog],2}); dis[V[jog]]=2;
while(!q.empty()){
int x=q.front().ff;
int y=q.front().ss;
q.pop();
if(y==1) C.pb(x);
else D.pb(x);
for(auto i : adj[x]){
if(dis[i.ff]) continue;
dis[i.ff]=y;
q.push({i.ff,y});
}
}
int ans=bin(C);
int ans1=bin(D);
answer(ans,ans1);
}
