#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define ff first
#define ss second
#define all(s) s.begin(),s.end()
#define rall(s) s.rbegin(),s.rend()
const int maxn=1e4+5;
namespace {
int N,D,H[maxn];
int U,A[maxn],B[maxn];
map<pair<int,int>,bool>mp;
set<int>g[maxn][100];
set<int>st[maxn];
set<int>s1,s2;
int blk;
}
void init(int N, int D, int H[]) {
::N=N,::D=D;
for(int i=0;i<N;i++){
::H[i]=H[i];
}
}
void curseChanges(int U, int A[], int B[]) {
::U=U;
for(int i=0;i<U;i++){
if(A[i]>B[i]) swap(A[i],B[i]);
::A[i]=A[i];
::B[i]=B[i];
}
mp.clear();
blk=sqrt(U);
for(int i=0;i<U;i++){
if(mp[{A[i],B[i]}]==false){
mp[{A[i],B[i]}]=true;
st[A[i]].insert(B[i]);
st[B[i]].insert(A[i]);
}
else{
mp[{A[i],B[i]}]=false;
st[A[i]].erase(B[i]);
st[B[i]].erase(A[i]);
}
if((i+1)%blk==0){
int C=(i+1)/blk;
for(int i=0;i<N;i++){
g[i][C]=st[i];
}
}
}
}
int question(int x, int y, int v) {
int ans=1e9;
s1=g[x][v/blk],s2=g[y][v/blk];
for(int d=v/blk*blk;d<v;d++){
if(A[d]==x){
if(s1.count(B[d])) s1.erase(B[d]);
else s1.insert(B[d]);
}
if(B[d]==x){
if(s1.count(A[d])) s1.erase(A[d]);
else s1.insert(A[d]);
}
if(A[d]==y){
if(s2.count(B[d])) s2.erase(B[d]);
else s2.insert(B[d]);
}
if(B[d]==y){
if(s2.count(A[d])) s2.erase(A[d]);
else s2.insert(A[d]);
}
}
vector<int>h1,h2;
for(auto z:s1){
h1.pb(H[z]);
}
for(auto z:s2){
h2.pb(H[z]);
}
sort(all(h1)),sort(all(h2));
auto i=0,j=0;
while(i<h1.size()&&j<h2.size()){
ans=min(ans,abs(h1[i]-h2[j]));
if(h1[i]<=h2[j]) i++;
else j++;
}
return ans;
}
