Scaramouche - 512!

you lived in some apartments, you lived in 511, since you moved you were attracted to your next door neighbor, scaramouche who lived in apartment 512, you developed a certain attraction to him as he was one of the few who seemed not interested in starting a conversation with you, one day you took the courage to knock on his door when a girl came out to open the door, you were planning to leave, when suddenly she said:
–Were you looking for my brother?
And you heard scaramouche asking
-Who is it?

.