var x,y:array[0..50000]of longint;
    n,i,j,k,a,b,c,d,dx,dy,nsx,njx,nsy,njy:longint;
    f:text;
begin
   assign(f,'tribute.in');
   reset(f);
   read(f,n,dx,dy);
   for i:=1 to n do
   begin
   read(f,a,b);
   if a>dx then begin c:=c+a-dx;
                      nsx:=nsx+1;
                end;
   x[a]:=x[a]+1;
   if b>dy then begin d:=d+b-dy;
                      nsy:=nsy+1;
                end;
   y[b]:=y[b]+1;
   end;
   close(f);
   i:=0;
   while c>c-nsx+njx+x[i] do
   begin
   i:=i+1;
   njx:=njx+x[i-1];
   c:=c-nsx+njx;
   nsx:=nsx-x[i+dx];
   end;
   i:=0;
   while d>d-nsy+njy+y[i] do
   begin
   i:=i+1;
   njy:=njy+y[i-1];
   c:=c-nsy+njy;
   nsy:=nsy-y[i+dy];
   end;
   assign(f,'tribute.out');
   rewrite(f);
   writeln(f,c+d);
   close(f);
end.