public static int beautifulPairs(List<Integer> A, List<Integer> B) {
        // create a frequency map to get the count of eacg val
        Map<Integer, Integer> freqMap = new HashMap<>();
        for(int val : A) freqMap.put(val, freqMap.getOrDefault(val, 0) + 1);
        //iterate over each val in b and accoridngly increment the amt of pairs
        int pairs = 0;
        for(int val : B){
            if(freqMap.containsKey(val) && freqMap.get(val) > 0){
                pairs++;
                freqMap.put(val, freqMap.getOrDefault(val, 0) - 1);
            }
        }
        //if amt of pairs == a.size(), decrease it because by 1 bc an element must be changed
        //else add 1 bc an element isnt paired
        return (pairs == A.size()) ? pairs - 1 : pairs + 1;
    }