#include <cstdio>
#include <algorithm>
using namespace std;
int n, m, x, y, xi, yi, d[5][50010], i, k[5];

pair<int, int> v[50010];

int cb(int c, int x){
    int p=1, u=k[c], m;
    while(p<=u)
    {
        m=(p+u)/2;
        if(c==3 || c==4)
        {
            if(-d[c][m]>-x)
                p=m+1;
            else
                u=m-1;
        }
        else
        {
            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[p].second;
    else
        d[c][ ++k[c] ]=v[p].second;
}

int main(){
    freopen("pachete.in", "r", stdin);
    freopen("pachete.out", "w", stdout);
    scanf("%d", &n);
    scanf("%d %d", &xi, &yi);
    for(i=1; i<=n; i++)
    {
        scanf("%d %d", &x, &y);
        v[i]=make_pair(x-xi, y-yi);
    }
    sort(v+1, v+n+1);
    for(i=1; i<=n; i++)
    {
        if(v[i].first<0)
        {
            if(v[i].second<0)
            {
                //cadranul 3
                if(k[3]==0)
                    d[3][ ++k[3] ]=v[i].second;
                else
                {
                    x=cb(3, v[i].second);
                    adauga(3, x, i);
                }
            }
            else
            {
                //cadranul 2
                if(k[2]==0)
                    d[2][ ++k[2] ]=v[i].second;
                else
                {
                    x=cb(2, v[i].second);
                    adauga(2, x, i);
                }
            }
        }
        else
        {
            if(v[i].second<0)
            {
                //cadranul 4
                if(k[4]==0)
                    d[4][ ++k[4] ]=v[i].second;
                else
                {
                    x=cb(4, v[i].second);
                    adauga(4, x, i);
                }
            }
            else
            {
                //cadranul 1
                if(k[1]==0)
                    d[1][ ++k[1] ]=v[i].second;
                else
                {
                    x=cb(1, v[i].second);
                    adauga(1, x, i);
                }
            }
        }
    }
    printf("%d", k[1]+k[2]+k[3]+k[4]);
    return 0;
}