#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pi;
typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
#define pb push_back
#define f first
#define s second
namespace debug {
const int DEBUG = false;
template<class T1, class T2>
void pr(const pair<T1, T2> &x);
template<class T, size_t SZ>
void pr(const array<T, SZ> &x);
template<class T>
void pr(const vector<T> &x);
template<class T>
void pr(const set<T> &x);
template<class T1, class T2>
void pr(const map<T1, T2> &x);
template<class T>
void pr(const T &x) { if (DEBUG) cout << x; }
template<class T, class... Ts>
void pr(const T &first, const Ts &... rest) { pr(first), pr(rest...); }
template<class T1, class T2>
void pr(const pair<T1, T2> &x) { pr("{", x.f, ", ", x.s, "}"); }
template<class T>
void prIn(const T &x) {
pr("{");
bool fst = 1;
for (auto &a : x) {
pr(fst ? "" : ", ", a), fst = 0;
}
pr("}");
}
template<class T, size_t SZ>
void pr(const array<T, SZ> &x) { prIn(x); }
template<class T>
void pr(const vector<T> &x) { prIn(x); }
template<class T>
void pr(const set<T> &x) { prIn(x); }
template<class T1, class T2>
void pr(const map<T1, T2> &x) { prIn(x); }
void ps() { pr("\n"); }
template<class Arg, class... Args>
void ps(const Arg &first, const Args &... rest) {
pr(first, " ");
ps(rest...);
}
}
using namespace debug;
ll ask(const vi &w);
void answer(int s, int t);
int N, M;
vi e1, e2;
ll A, B;
vector<vector<pi>> aList;
ll base;
vi query;
int searchE() {
int low = 0;
int high = M - 1;
while (low != high) {
int mid = (low + high) / 2;
for (int i = 0; i < M; i++) {
query[i] = i <= mid;
}
ll res = ask(query);
if (res == base) {
low = mid + 1;
} else {
high = mid;
}
}
return low;
}
vi dist[3];
int cT;
void fDist(int r) {
queue<int> q;
q.push(r);
dist[cT][r] = 0;
while (q.size()) {
int cV = q.front();
q.pop();
for (pi aE : aList[cV]) {
if (dist[cT][aE.f] == -1) {
dist[cT][aE.f] = dist[cT][cV] + 1;
q.push(aE.f);
}
}
}
}
vi t, pE;
void bTree(int r, vi &mbr) {
queue<int> q;
q.push(r);
for (int j = 0; j < N; j++) {
dist[cT][j] = -1;
}
dist[cT][r] = 0;
mbr.pb(r);
while (q.size()) {
int cV = q.front();
q.pop();
for (pi aE : aList[cV]) {
if (t[aE.f] == cT && dist[cT][aE.f] == -1) {
dist[cT][aE.f] = dist[cT][cV] + 1;
mbr.pb(aE.f);
query[aE.s] = 0;
pE[aE.f] = aE.s;
q.push(aE.f);
}
}
}
}
bool cmp(int a, int b) {
return dist[cT][a] < dist[cT][b];
}
int find(vi &mbr) {
sort(mbr.begin(), mbr.end(), cmp);
reverse(mbr.begin(), mbr.end());
if (cT == 0) {
ps("srtd");
ps(mbr);
}
//decreasing dist
int low = 0;
int high = mbr.size() - 1;
while (low != high) {
int mid = (low + high) / 2;
for (int i = 0; i < mbr.size(); i++) {
int cE = pE[mbr[i]];
if(cE >= 0){
query[cE] = i <= mid;
}
}
ll res = ask(query);
if (res == base) {
low = mid + 1;
} else {
high = mid;
}
}
for (int i = 0; i < mbr.size(); i++) {
int cE = pE[mbr[i]];
if(cE >= 0){
query[cE] = 0;
}
}
return mbr[low];
}
void find_pair(int iN, vi ie1, vi ie2, int iA, int iB) {
ps("start");
N = iN;
e1 = ie1, e2 = ie2;
A = iA, B = iB;
aList.resize(N);
M = e1.size();
for (int i = 0; i < M; i++) {
aList[e1[i]].pb({e2[i], i});
aList[e2[i]].pb({e1[i], i});
}
vi empty(M);
for(int i = 0; i < M; i++){
empty[i] = 0;
}
base = ask(empty);
ps(base);
query.resize(M);
int split = searchE();
ps("split", split, e1[split], e2[split]);
dist[0].resize(N);
dist[1].resize(N);
for (int j = 0; j < N; j++) {
dist[0][j] = -1;
dist[1][j] = -1;
}
cT = 0;
fDist(e1[split]);
cT = 1;
fDist(e2[split]);
ps("dist");
ps(dist[0]);
ps(dist[1]);
t.resize(N);
pE.resize(N);
for (int i = 0; i < N; i++) {
pE[i] = -1;
}
for (int i = 0; i < N; i++) {
t[i] = dist[0][i] > dist[1][i];
}
for (int i = 0; i < M; i++) {
query[i] = 1;
}
query[split] = 0;
vi mbrS, mbrT;
cT = 0;
bTree(ie1[split], mbrS);
cT = 1;
bTree(ie2[split], mbrT);
ps("mbr");
ps(mbrS);
ps(mbrT);
ps("query");
ps(query);
ps("pE");
ps(pE);
cT = 0;
int s = find(mbrS);
cT = 1;
int t = find(mbrT);
ps(s, t);
answer(s, t);
}
