#include "highway.h"
#include <bits/stdc++.h>
using namespace std;
//macros
typedef long long ll;
typedef pair<int, int> ii;
typedef tuple<int, int, int> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<ll> vll;
#define REP(a,b,c) for(int a=int(b); a<int(c); a++)
#define RE(a,c) REP(a,0,c)
#define RE1(a,c) REP(a,1,c+1)
#define REI(a,b,c) REP(a,b,c+1)
#define REV(a,b,c) for(int a=int(c-1); a>=int(b); a--)
#define INF 1e9
#define pb push_back
#define fi first
#define se second
#define sz size()
//===================//
// begin program //
//===================//
const int MX = 5e5;
int n, m, a, b;
vi w, u, v;
vi group, visited;
bool sameGroup() {
RE(i,m) {
if(group[u[i]] != group[v[i]]) w[i] = 0;
else w[i] = 1;
}
ll dist = ask(w);
return dist%2;
}
void find_pair(int N, vi U, vi V, int A, int B) {
n=N; a=A; b=B; u=U; v=V;
m = u.sz;
// A == 1 and B == 2
w.resize(m);
group.resize(n);
int XOR=0;
RE(i,17) {
int bit = (1<<i);
RE(j,n) group[j] = (j&bit)==0;
if(sameGroup()) XOR |= bit;
}
visited.assign(n, 0);
RE(i,n) {
if(visited[i]) continue;
if((i^XOR) < n) {
group[i] = 0; group[i^XOR] = 1;
visited[i] = visited[i^XOR] = 1;
} else {
group[i] = 0;
visited[i] = 1;
}
}
int ones=0;
RE(i,n) if(group[i]) ones++;
while(ones != 1) {
set<int> rem;
RE(i,n) {
if(group[i] && rem.sz != ones/2) {
rem.insert(i);
group[i] = 0;
}
}
if(sameGroup()) {
RE(i,n) group[i] = 0;
for(int i:rem) group[i] = 1;
}
ones=0;
RE(i,n) if(group[i]) ones++;
}
int ans = 0;
RE(i,n) if(group[i]) ans = i;
answer(ans, ans^XOR);
}
