public static int pickingNumbers(List<Integer> a) {
    // Write your code here
        Collections.sort(a);
        int max = 0;
        int total = 0;
        boolean diffNumber = false;
        for (int i = 0; i < a.size() - 1; i++) {
            if (a.get(i + 1) - a.get(i) == 0) {
                total++;   
            } else if (a.get(i + 1) - a.get(i) == 1 && !diffNumber) {
                total++;
                diffNumber = true;
            } else {
                total = 0;
                diffNumber = false;
            }
            
            if (total > max)
                max = total;
        }
        return max + 1;
    }