#include<bits/stdc++.h>
#define ll long long
const int N=1e6+5;
//const ll mod=998244373;
using namespace std;

int n,t;
int x[N],y[N],p[N];
int cnt,ans;

int main()
{
	srand(time(0));
	//ios_base::sync_with_stdio(0);
    //cin.tie(0);
	while(scanf("%d",&n)!=EOF)
	  {
	  	cnt=0;
	  	if(n==1)
	  	  {
	  	  	printf("1\n");
	  	  	continue;
	  	  }
	  	if(n==2)
	  	  {
	  	  	printf("2\n");
	  	  	continue;
	  	  }
	  	queue<pair<int,int>>q;
	    for(int i=1;i<=n;++i)
	      {
	      	cin>>x[i]>>y[i];
	        p[i]=i;
	      } 
	    random_shuffle(p+1,p+1+n);
        for(int i=1;i<=n;++i)
          {
          	int g=p[i];
          	q.push({x[g],y[g]});
          }
        int nx1=q.front().first;
        int ny1=q.front().second;
        q.pop();
        int nx2=q.front().first;
        int ny2=q.front().second;
        q.pop();
        while(!q.empty())
          {
          	//++cnt;
          	if(cnt==10000)
          	  break;
            int nx3=q.front().first;
            int ny3=q.front().second;
            q.pop();

            if(nx1==nx2&&nx2==nx3)
              {
              	++cnt;
              	q.push({nx3,ny3});
              	continue;
              }
            if(ny1==ny2&&ny2==ny3)
              {
              	++cnt;
              	q.push({nx3,ny3});
              	continue;
              }
               if(!q.size())
              break;
            nx1=q.front().first;
            ny1=q.front().second;
            q.pop();
            nx2=q.front().first;
            ny2=q.front().second;
            q.pop();
          }
        if(q.size())
          printf("%d\n",q.size()+2);
        else
          printf("0\n");
     }
}