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

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(){
    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);
        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(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(j=2; j<=nr[i]; j++)
            {
                x=cb(i, v[i][j].second);
                adauga(i, x, j);
            }
        }
    printf("%d", k[1]+k[2]+k[3]+k[4]);
    return 0;
}