D is B's father. B is C's Sister-in-Law and A's daughter. What is A's relationship to D?

In a certain code language: 'A + B' means 'A is the son of B' 'A - B' means 'A is the brother of B' 'A × B' means 'A is the wife of B' 'A ÷ B' means 'A is the father of B' Based on the above, how is L related to P if the expression is 'L + M ÷ N × O - P'?

A man said, 'The boy playing with my son is the son of my wife's sister.' How is the boy related to the man?