#include <stdio.h>
#include <math.h>

int x[50000],y[50000];

int compare(const void*a,const void*b)
{
    return *(int*)a-*(int*)b;
}

int main()
{
    int n,l,w,i,j,s=0;
    FILE*fi,*fo;
    fi=fopen("tribute.in","r");
    fo=fopen("tribute.out","w");
    fscanf(fi,"%d%d%d",&n,&l,&w);
    for(i=0;i<n;i++){
        fscanf(fi,"%d%d",&x[i],&y[i]);
    }
    qsort(x,n,sizeof(int),compare);
    qsort(y,n,sizeof(int),compare);
    i=0;
    j=n-1;
    while(i<=j){
    if(x[j]-x[i]-l>0)
      s+=x[j]-x[i]-l;
    if(y[j]-y[i]-w>0)
      s+=y[j]-y[i]-w;
    i++;
    j--;
    }
    fprintf(fo,"%d",s);
    fclose(fi);
    fclose(fo);
    return 0;
}