Helmut Lang asymmetrical black dress, EUC

This dress is modern and sophisticated. It features so many thoughtful details: it is lined, the hem is asymmetrical and flattering to the legs, showing just a peek of a knee. The wide vertical pleat as not fully attached, but creates a fancy silhouette. The sleeves have unfinished leather hems. The size is marked as a P, which is petite, but has no number. The pit to pit measures 14.5”. I think it is an S or XS