import java.util.Arrays;
import java.util.stream.Stream;

public class C4Q9 {
    public static void main(String[] args) {
        String[] a = {"a", "aa", "aaa", "aaaa", "aaaaa"};
        String[] res = filter(a, (s) -> {
            return s.length() <= 3;
        });

        for (String s : res) {
            System.out.println(s);
        }
    }

    public static String[] filter(String[] a, Filter f) {
        return Arrays.stream(a).filter((s) -> {
            return f.accept(s);
        }).toArray(String[]::new);
    }
}