A + B means A is the father of B ;
A - B means A is the wife of B ;
A x B means A is the brother of B ;
A ÷ B means A is the daughter of B.
A is the son of B.
C, B`s sister has a son D and a daughter E.
F is the maternal uncle of D.
Arun said, "This girl is the wife of the grandson of my mother."
Who is Arun to the girl ?