#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
int n,cnt,i,j,k,aux,x,st,dr,mid,nrdr,CXpos,CYpos,minim[50001],pos,adv;
pair <int,int> clnt[50001];
int main(){
    ifstream fin("pachete.in");
    ofstream fout("pachete.out");
    fin>>n;
    fin>>clnt[50000].first>>clnt[50000].second;
    for(i=0;i<n;i++){
        fin>>clnt[i].first>>clnt[i].second;
    }
    //sort(clnt,clnt+n);
    for(i=0;i<n;i++){
        minim[i]=abs(clnt[i].first-clnt[50000].first)+abs(clnt[i].second-clnt[50000].second);
    }
    adv=1;
    while(adv==1){
        adv=0;
        CXpos=clnt[50000].first; CYpos=clnt[50000].second; pos=50000;
        while(pos!=aux){
            aux=pos; 
            for(i=0;i<n;i++){
                if(clnt[i].first!=-1){
                    adv=1;
                    if(minim[i]==(abs(CXpos-clnt[i].first)+abs(CYpos-clnt[i].second)+minim[pos])){
                        CXpos=clnt[i].first;
                        CYpos=clnt[i].second;
                        clnt[i].first=-1;
                        pos=i;
                        //cout<<CXpos<<" "<<CYpos<<" "<<i<<'\n';
                        break;
                    }
                }
            }
            if(pos==aux&&pos!=50000){
                nrdr++;
            }
            //cout<<1<<'\n';
        }
    }
    fout<<nrdr;
    fin.close();
    fout.close();
    return 0;
}