In a certain code language: 'A + B' means 'A is the sister of B', 'A - B' means 'A is the brother of B', 'A & B' means 'A is the wife of B', and 'A $ B' means 'A is the father of B'. How is R related to D if 'R $ A + S - E & 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?