#include<bits/stdc++.h>
using namespace std;
int n,cnt;
int vis[2005][2005];
int Is[2005][2005];
int dotx[] = {-1,-1,0,0,1,1};
int doty[] = {-1,0,-1,1,0,1};
void bfs(int x,int y)
{
	queue<pair<int,int> > q;
	q.push({x,y});
	vis[x][y] = 1;
	while(!q.empty())
	{
		int a = q.front().first,b = q.front().second;
		//狠狠批评 宽搜不弹出 
		q.pop(); 
		for(int i=0;i<6;i++)
		{
			int t1 = a+dotx[i],t2 = b+doty[i];
			if(!vis[t1][t2] && Is[t1][t2])
			{
				vis[t1][t2] = 1;
				q.push({t1,t2});
			}
		}
	}
}
int main()
{
	cin >> n;
	for(int i=1;i<=n;i++)
	{
		int x,y;
		cin >> x >> y;
		Is[x+1001][y+1001] = 1;
	}
	for(int i=1;i<=2001;i++)
		for(int j=1;j<=2001;j++)
			if(!vis[i][j] && Is[i][j]) {
				bfs(i,j);
				cnt++;
			}
	cout << cnt;
	return 0;
}