Program ograzi;
var n,w,h,i,j,a,b,k,p : longint;
    M : array[0..1000000,0..10000] of 0..5;
    b1,b2 : array [0..1 shl 17] of char;


begin
   assign(input,'ograzi.in'); settextbuf(input,b1); reset(input);
   assign(output,'ograzi.out'); settextbuf(output,b2); rewrite(output);
   readln(n,p,w,h);
   for i:=1 to n do begin
                         readln(a,b);
                         for j:=a to a+w do
                             for k:=b to b+h do
                                M[j,k]:=1;
                     end;
   k:=0;
   for i:=1 to p do begin
                          readln(a,b);
                          if M[a,b]=1 then k:=k+1;
                    end;
   writeln(k);
   close(input);
   close(output) ;
end.