6.4. On an island, there live 456 aborigines, each of whom is either a knight, who always tells the truth, or a liar, who always lies. All residents have different heights. One day, each aborigine said: "All other residents are shorter than me!". What is the maximum number of aborigines who could have said a minute later: "All other residents are taller than me!"?

Answer, option 1. 2019.

Answer, option 2. 998.

Answer, option 3. 498.

Answer, option 4. 454.
Solution Variant 1. Evaluation. Consider the tallest and the shortest aborigines. For each of them, one of the spoken phrases is true, the other is false. Therefore, no matter who they are - knights or liars - none of them could have spoken the second phrase a minute later. Thus, the number of spoken phrases is no more than $2021-2=2019$.

Example. We will provide an example showing that all aborigines, except for two, could have spoken the second phrase. Let the heights of the aborigines be $1,2,3, \ldots, 2021$. The first one is a knight, and the rest are liars. Then on the first day, all can speak the phrase: for the first one, it will be true, and for the rest, it will be false. The next day, the phrase can be spoken by all aborigines except the shortest and the tallest, that is, 2019 people.