Task: Question Answering
Input (English): Passage: Barbra Streisand portrays Yentl Mendel, a girl living in an Ashkenazi shtetl named Pechev in Poland in 1904. Yentl's father, Rebbe Mendel, secretly instructs her in the Talmud despite the proscription of such study by women according to the custom of her community.
After the death of her father, Yentl decides to cut her hair short, dress like a man, take her late brother's name, Anshel, and enter a Jewish religious school in Bychawa. Upon entering the yeshiva, Yentl befriends a fellow student, Avigdor, and meets his fiancée, Hadass. Things get complicated when Hadass's family cancels her wedding to Avigdor over fears that his family is tainted with insanity (his brother committed suicide), and decides that she should marry Anshel instead. Meanwhile, Hadass develops romantic feelings for Yentl, while Yentl herself is falling in love with Avigdor. After much turmoil, Avigdor and Hadass are reunited, while Yentl leaves Europe to go to the United States, where she hopes to lead a life with more freedom. 
Question: What surname does the girl who Hadass develops feelings for have?
Output (English): Mendel.