ss

import java.util.*;
import java.util.concurrent.*;

class Main {
    public static void main(String[] args) {
        System.out.println("Try programiz.pro");

        List<Integer> list = new ArrayList<>();
        list.add(1);
        list.add(2);
        list.add(3);
        list.add(1);

        System.out.println(duplicate(list));
        list.add(2);
        list.add(3);
        System.out.println(duplicate(list));
    }

    private static List<Integer> duplicate(List<Integer> nlist) {
        Set<Integer> ans = new HashSet<>();
        Map<Integer, Integer> map = new HashMap<>();

        for (Integer i: nlist) {
            map.computeIfAbsent(i, k-> 0);
            map.put(i, map.get(i)+1);
        }

        Iterator<Integer> itr = map.keySet().iterator();
        boolean changed = true;
        while(changed) {
            changed = false;
            Map<Integer, Integer> nextmap = new HashMap<>();

            for (Map.Entry<Integer, Integer> e: map.entrySet()) {
                int count = e.getValue();
                int k  = e.getKey();

                if (count != 1) {
                    k = k*count;
                    changed = true;
                }
                nextmap.put(k, nextmap.getOrDefault(k, 0) + 1);
            }
            map = nextmap;

        }
        return new ArrayList<>(map.keySet());

    }
}