Miguel bought an old house near Mallorca. Like all houses, it has a patio with a length of 12 meters and a width of 9 meters. Migai wants to plant 10 trees in it. His neighbor told him that no matter how he sowed, there would be at least two trees every five meters.

Do you think his neighbor is right? Before you answer, please send a picture back, and try to put this 10 tree at a distance of more than 5 meters.

Did you do it? (Check all your answers together), does his neighbor make sense? If you think so, please prove that no matter how this 10 tree is placed, at least two trees will be less than 5 meters apart.

A famous mathematician once mentioned a theory called Drichlet, which may be helpful to you. This theory is also called El principio del palomar pigeon theory. It is mentioned in theory that if there are three holes and four pigeons in a pigeon nest, then there must be two pigeons going into one hole to live together.

Try to apply this theory to your problem. Four pigeons are equivalent to 10 tree, and three holes are equivalent to. . . . . .

Now that you understand El principio del palomar's pigeon theory, can you prove that two people in Mallorca have the same amount of hair? (Not counting two bald men)