ОГЭ

var
  a,k,s : integer;
begin
  k := 0;
  s := 0;
  readln(a);
  while a <> 0 do
  begin
    if a mod 4 = 0 then
    begin
      s := s + a;
      k := k + 1;
    end;
    readln(a);
  end;
  if k = 0 then writeln('NO') else writeln(s/k);
end.