public class Solution {
    public static HashSet<Integer> createSet() {
        HashSet<Integer> numbers = new HashSet<Integer>();
        for (int i=0; i<20; i++) {
            numbers.add(i);
        }
        return numbers;

    }

    public static HashSet<Integer> removeAllNumbersMoreThan10(HashSet<Integer> set) {
        ArrayList<
        for (int n : set) {
            if (n>10) {
                set.remove(n);
            }
        }
        return set;

    }

    public static void main(String[] args) {
    }
}