There are 21 people, everyone hugs each other, but the person hugging cant hug themself, so (21*21)-21
(21*21) -21 = 441
441-21=420
There are 21 people, everyone hugs each other, but the person hugging cant hug themself, so (21*21)-21
(21*21) -21 = 441
441-21=420
All credit to sulgeorge
