#include<fstream>
using namespace std;
int n, i, x, y, xmin, ymin, dx, dy, nrp;
int v[50001], w[50001], fx[50003], fy[50003], sx[50003], sy[50003];
ifstream fin("tribute.in");
ofstream fout("tribute.out");
int main(){
    fin>> n >> dx >> dy;
    for(i = 1; i <= n; i++){
        fin>> x >> y;
        v[x] ++;
        w[y] ++;
    }
    nrp = v[50000];
    for(i = 49999; i >= 0; i--){
        fx[i] = fx[i+1] + nrp;
        nrp += v[i];
    }
    nrp = w[50000];
    for(i = 49999; i >= 0; i--){
        fy[i] = fy[i+1] + nrp;
        nrp += w[i];
    }
    nrp = v[0];
    for(i = 1; i <= 50000; i++){
        sx[i] = sx[i-1] + nrp;
        nrp += v[i];
    }
    nrp = w[0];
    for(i = 1; i <= 50000; i++){
        sy[i] = sy[i-1] + nrp;
        nrp += w[i];
    }
    xmin = fx[dx];
    for(i = 1; i <= 50000-dx; i++){
        if(xmin > fx[i+dx] + sx[i]){
            xmin = fx[i+dx] + sx[i];
        }
    }
    ymin = fy[dy];
    for(i = 1; i <= 50000-dy; i++){
        if(ymin > fy[i+dy] + sy[i]){
            ymin = fy[i+dy] + sy[i];
        }
    }
    fout<< xmin + ymin;
    return 0;
}