And you in school years, too, dad taught you to remember the multiplication (+) to (-)this is the following:
Is it a friend? is it an enemy?

We receive :
The friend of your enemy is the enemy of you.and (- )
A friend of your friend = a friend of you.and (+)
The enemy of your enemy is your friend.and (+)
The enemy of your friend = the enemy of you.( )

Which of the parents might need it.)