#include<algorithm>
using namespace std;
#define N 50002
long x[N],y[N],n,dx,dy,i;

int c(long a,long b)
{return a<b;}
      
long h(long x[N],long dx)
{long k,j,m=N,s[N]={0},z[N]={0},p[N],r[N];
sort(x+1,x+n+1,c),j=x[n]-dx;
for(i=1;i<=n;i++)
      z[x[i]]++,s[x[i]]++;
for(i=x[1];i<=j;i++)
      {z[i-1]+=z[i-2],p[i]=p[i-1]+z[i-1];
      s[j+dx-i+1]+=s[j+dx-i+2];
      r[i]=r[i-1]+s[j+dx-i+1];}
for(i=x[1];i<=j;i++)
if(m>(k=p[i]+r[j-i]))
      m=k;
return m;}

int main()
{FILE *f=fopen("tribute.in","r"),*g=fopen("tribute.out","w");
fscanf(f,"%ld%ld%ld",&n,&dx,&dy);
for(i=1;i<=n;i++)
      fscanf(f,"%ld%ld",&x[i],&y[i]);
fprintf(g,"%ld",h(x,dx)+h(y,dy));
return 0;}