class Solution {
    public int findLHS(int[] nums) {
        HashMap<Integer, Integer> map = new HashMap<>();
        
        for(int num: nums)
            map.put(num, map.getOrDefault(num,0)+1);
        
        int res = 0;
        
        for(int key: map.keySet())
            if(map.containsKey(key+1))
                res = Math.max(res, map.get(key)+map.get(key+1));
        
        return res;
    }
}