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Each group consists of 6 people or 3 mutual friends, or from 3 total strangers. Prove it.

A: We take the human H. Of the five others, or need to be at least three acquaintances X or at least three strangers for X. Assume that X has three strangers A, B, C. If A, B, C is not required triad familiar, they should include a couple of strangers, for example A and B. Then X, A, B - required triad of strangers.