import java.util.List;
import java.util.TreeSet;

public class emptyPaper {

  public static void main(String[] args) {
    TreeSet<Integer> set = new TreeSet<>(List.of(1, 2, 3, 4));
    System.out.println(set.first()); // 1
    System.out.println(set.last()); // 4
  }
}