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#include <cstdio>
#include <iostream>

using namespace std;

int px[50001],py[50001];

int main()
{
    freopen("tribute.in","r",stdin);
    freopen("tribute.out","w",stdout);
    int n,dx,dy;
    int sx=0,sy=0;
    cin>>n>>dx>>dy;
    
    for(int i=0;i<n;i++)
    {
        int a,b;
        cin>>a>>b;
        sx+=a;
        sy+=b;
        px[a]+=1;
        py[b]+=1;
    }
    
    int mnx=-1,mny=-1,mnxp,mnyp;
    int l=0,r=n;
    
    for(int i=0;i<=50001;i++)
    {
        r-=px[i];
        if(i>=dx) l+=px[i-dx];
        sx=sx-r+l;
        if(i>=dx&&(mnx>sx||mnx==-1)) {mnx=sx;mnxp=i-dx+1;}
    }
    l=0; r=n;
    for(int i=0;i<=50001;i++)
    {
        r-=py[i];
        if(i>=dy) l+=py[i-dy];
        sy=sy-r+l;
        if(i>=dy&&(mny>sy||mny==-1)) {mny=sy;mnyp=i-dy+1;}
    }
    cout<<mnx+mny;
    return 0;
}