Thread:Snowdog67/@comment-31677686-20180215191136/@comment-30339728-20180215203615

I think it's 12 also:

Person #1 shakes 11 other people and is done = 11 shakes

Person #2 shakes 10 others (since #1 already got him/her) = 21

Person #3 shakes 9 (see #2 explanations) = 30

Person #4 shakes 8 = 38

Person #5 shakes 7 = 45

Person #6 shakes 6 = 51

Person #7 shakes 5 = 56

Person #8 shakes 4 = 60

Person #9 shakes 3 = 63

Person #10 shakes 2 = 65

Person #11 shakes 1 = 66