#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int mxN = 2e3+10;
int p[mxN], n, s[mxN][mxN];
set<int> comp;
int get(int x) {
return (p[x] < 0 ? x : p[x] = get(p[x]));
}
void uni(int x, int y) {
x = get(x); y = get(y);
if(x == y) return ;
if(p[x] > p[y]) swap(x, y);
comp.erase(y);
for(auto it : comp) {
if(it == x) continue;
s[x][it] = s[it][x] = s[x][it] + s[y][it];
}
p[x] += p[y];
p[y] = x;
}
int hasEdge(int a, int b) {
if(s[get(a)][get(b)] == 1) {
uni(a, b);
return 1;
}
--s[get(a)][get(b)];
return 0;
}
void initialize(int N) {
n = N;
for(int i = 0; i < n; i++) p[i] = -1;
for(int i = 0; i < n; i++) {
for(int j = i+1; j < n; j++) {
s[get(i)][get(j)] = s[get(j)][get(i)] = 1;
}
comp.insert(i);
}
}
/*
int main()
{
initialize(4);
cout << hasEdge(0, 1) << hasEdge(3, 0) << hasEdge(1, 2) << hasEdge(0, 2);
cout << hasEdge(3, 1) << hasEdge(2, 3);
}*/
