public static void main(String[] args) {
        PDD1();
    }
    public static void PDD1(){
        long sum = 1;
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        List<Long> arrayList = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            arrayList.add(scanner.nextLong());
        }
        arrayList.sort((o1, o2) -> {
            Long tmp = o2-o1;
            return tmp.intValue();
        }
        );
        if (arrayList.get(1)*arrayList.get(2)<arrayList.get(arrayList.size()-1)*arrayList.get(arrayList.size()-2)){
            sum = arrayList.get(0)*arrayList.get(arrayList.size()-1)*arrayList.get(arrayList.size()-2);
        }else {
            sum = arrayList.get(0)*arrayList.get(1)*arrayList.get(2);
        }
        System.out.println(sum);
    }