public static void main(String[] args) throws Exception {
        ArrayList<Integer> list=new ArrayList<>();
        ArrayList<Integer> list1=new ArrayList<>();
        Scanner scanner =new Scanner(System.in);
        for (int i = 0; i < 20; i++) {
            list1.add(scanner.nextInt());
        }
        for (int i = 0; i < 20; i++) {
            if (list.get(i)%2==0) list1.get(i)=list.get(i);//why mistake ?"variable expected "
        }
}