Pigeonhole principle constellation _ Pigeonhole principle constellation

There are twelve constellations, but there are thirteen people Assume that the constellations of the first twelve people do not repeat. Then the thirteenth person must repeat one of them.

This kind of problem is not particularly difficult. It can be described in words: there are twelve constellations, but there are thirteen people.

So 13- 12= 1.

So it must be two people in the same constellation.