What an easy one!

Eu pensei inicialmente em 301, pela fórmula do $25 \times 12$ +1. Mas após raciocinar um pouco, lembrei do fato de que Mohhawk sabia seu aniversário, não precisando de pessoas para preencher 12 meses. Ou seja, a fórmula final é $24 \times 12$ +1.

OBS: O nome dessa matéria é "Princípio das casas dos pombos", caso queira estudá-la.

Initially, I thought in 301, by using $25 \times 12$ +1. But this wasn't right, then I remembered that Mohhawk already knew his birthday. So he didn't need 12 people, only himself. So it's not $25 \times 12$ +1, but $25 \times 12$ +1-12, which is equal to $24 \times 12$ +1.

1 year has 12 months. If 12 people have different birth months, the 13rd person WILL CERTAINLY fit one of the twelve months [of a year]. So you need 12x+1 people to be certain that at least x of them have the same birth month.

*PS: The image don't have Mohhawk represented. He is the (+1). Each box represents one month and each month has 24 dots. To have 25, you you need one more person (Mohhawk).