public static int sockMerchant(int n, List<Integer> ar) {
    // Write your code here
        Map<Integer,Integer> colorCount =new HashMap<>();
        for(int sock : ar ){
            colorCount.put(sock, colorCount.getOrDefault(sock,0)+1);
        }
        
        Integer pairs = 0;
        for(Integer c : colorCount.values()){
            pairs+=c/2;
            

        }
        return pairs;

    }

}