program preONI_3_3;
var
  terulet: array[0..200,0..200] of byte;
  jsz, tsz, h, sz, i, j, k, x ,y, jz: longint;
  f :text;

procedure Load;
begin
  Assign(f, 'ograzi.in');
  Reset(f);
  ReadLn(f, tsz, jsz, sz, h);
  for i := 1 to tsz do
    begin
      Readln(f, x, y);
      for j := sz downto 0 do
        for k := 0 to h do
          terulet[x + j,y + k] := 1;
    end;
end;

jz := 0;
Begin
  Load;
  for i := 1 to jsz do
    begin
      Readln(f, x, y);
      if terulet[x,y] = 1 then Inc(jz);
    end;
  Close(f);
  Assign(f, 'ograzi.out');
  ReWrite(f);
  WriteLn(f, jz);
  Close(f);
end.