Open transfer item Party A+Party B > =2ab
Add 2ab on both sides.
Party A+Party B+2AB > =2ab+2ab
(a+b) square >; =4ab
Two sides are divided into ab(a+b).
Ab score (a+b) > =(a+b) 4 points
a+b & gt； =(a+b) 4 points
1in a+(1in b) > = (a+b) 4 points.