# In Excursion 36 people that p1, p2, ., p36 meet and shake hands in a circular fashion. In other words, there are totally 36 handshakes involving the pairs, {p1, p2}, {p2, p3},...., {p35, p36}, {p36, p1}. Then size of the smallest set of people such that the rest have shaken hands with at least one person in the set is