#include <fstream>
using namespace std;
ifstream fin ("tribute.in");
ofstream fout ("tribute.out");
int n,a,b,i,x,y,minx,miny;
int frx[50001],fry[50001],ssx[50001],sdx[50001],ssy[50001],sdy[50001];
int main()
{
    ///minimul pe ox+minimul pe oy
    fin>>n>>a>>b;
    for (i=1; i<=n; i++)
    {
        fin>>x>>y;
        frx[x]++;
        fry[y]++;
    }
    ssx[0]=frx[0];
    for (i=1; i<=50000; i++)
        ssx[i]=ssx[i-1]+frx[i];
    sdx[50000]=frx[50000];
    for (i=49999; i>=0; i--)
        sdx[i]=sdx[i+1]+frx[i];
    minx=ssx[0]+sdx[a];
    for (i=1; i<=50000-a; i++)
        minx=min (minx,ssx[i]+sdx[i+a]);
    ssy[0]=fry[0];
    for (i=1; i<=50000; i++)
        ssy[i]=ssy[i-1]+fry[i];
    sdy[50000]=fry[50000];
    for (i=49999; i>=0; i--)
        sdy[i]=sdy[i+1]+fry[i];
    miny=ssy[0]+sdy[b];
    for (i=1; i<=50000-b; i++)
        miny=min (miny,ssy[i]+sdy[i+b]);
    fout<<minx+miny;
    return 0;
}