#include <fstream>
#include <algorithm>

using namespace std;

ifstream fin ("pachete.in");
ofstream fout ("pachete.out");

int n, m, x, y, xi, yi, d[5][50010], k[5], nr[5];

pair<int, int> v[5][50010];

int cb(int c, int x)
{
    int p=1, u=k[c], m;
    while(p<=u)
    {
        m=(p+u)/2;
        if(d[c][m]>x) p=m+1;
        else u=m-1;
    }
    return p;
}

void adauga(int c, int x, int p)
{
    if(d[c][x]!=0) d[c][x]=v[c][p].second;
    else d[c][ ++k[c] ]=v[c][p].second;
}

int main()
{

    fin >> n >> xi >> yi;
    for(int i=1; i<=n; i++)
    {
        fin >> x >> y;
        x-=xi;
        y-=yi;
        if(x<0)
            if(y<0)v[3][ ++nr[3] ]=make_pair(-x, -y);
            else v[2][ ++nr[2] ]=make_pair(-x, y);
        else
            if(y<0)v[4][ ++nr[4] ]=make_pair(x, -y);
            else v[1][ ++nr[1] ]=make_pair(x, y);
    }
    for(int i=1; i<5; i++)
        if(nr[i]>0)
        {
            sort(v[i]+1, v[i]+nr[i]+1);
            d[i][ ++k[i] ]=v[i][1].second;
            for(int j=2; j<=nr[i]; j++)
            {
                x=cb(i, v[i][j].second);
                adauga(i, x, j);
            }
        }
    fout << k[1] +k[2]+k[3]+k[4];
    return 0;
}