Пре­об­ра­зуй­те, если это не­об­хо­ди­мо, слово WELL так, чтобы оно грам­ма­ти­че­ски со­от­вет­ство­ва­ло со­дер­жа­нию тек­ста.

His real name was Samuel Langhorne Clemens. However, he is __________________ known by his pen name, Mark Twain.