class Solution {
    public int minSetSize(int[] arr) {
        int count=0, sum=0;
        Map<Integer, Integer> map = new HashMap<>();
        for(int n: arr){
            map.put(n, map.getOrDefault(n, 0) +1);
        }
        List<Map.Entry<Integer, Integer>> list = new LinkedList<>(map.entrySet());
        Collections.sort(list, (i1, i2) -> i2.getValue().compareTo(i1.getValue()));
        for (Map.Entry<Integer, Integer> aa : list) {
            sum+=aa.getValue();
            count++;
            if(sum>=arr.length/2){
                return count;
            }
        }
        return -1;
    }
}