For María Isabel Salazar López, the hardest thing about being the new girl in school is that the teacher doesn't call her by her real name. "We already have two Marías in this class," says her teacher. "Why don't we call you Mary instead?" <P>But María Isabel has been named for her Papá's mother and for Chabela, her beloved Puerto Rican grandmother. Can she find a way to make her teacher see that if she loses her name, she's lost the most important part of herself?