---

var
  s: string;
  i, code, num: longint;
  ans: int64;
begin
  ReadLn(s);
  ans := 0;
  for i := 1 to Length(s) do
  begin
    Val(s[i], num, code);
    if num mod 4 = 0 then
      ans := ans + 1;
    if i > 1 then
    begin
      Val(Copy(s, i - 1, 2), num, code);
      if num mod 4 = 0 then
        ans := ans + (i - 1);
    end;
  end;
  WriteLn(ans);
end.