public List<Integer> function(List<Integer> A, List<Integer> B) {
        List<Integer> C = new ArrayList<>();

        Map<Integer, Long> howManyTimesAppearsInList = B.stream()
                .collect(Collectors.groupingBy(x -> x, Collectors.counting()));

        for (int element : A) {
            Long occurrences = howManyTimesAppearsInList.get(element);
            if (occurrences == null) {
                C.add(element);
            } else {
                if (occurrences == 1) {
                    C.add(element);
                } else {
                    for (int j = 2; j < element; j++) {
                        if (element % j == 0) {
                            C.add(element);
                            break;
                        }
                    }
                }
            }
        }
        return C;
    }