import java.util.ArrayList;

public class CustomArrayList<E> extends ArrayList<E> {

    // Override add method to prevent duplicates
    @Override
    public boolean add(E e) {
        if (!contains(e)) {
            return super.add(e);
        }
        return false;
    }

    public static void main(String[] args) {
        CustomArrayList<Integer> list = new CustomArrayList<>();
        list.add(1);
        list.add(2);
        list.add(3);
        list.add(2); // This duplicate will not be added

        System.out.println(list); // Output: [1, 2, 3]
    }
}