int numCollisions = 0;
        Set<Integer> hashes = new HashSet<>();
        Set<Integer> collisions = new HashSet<>();
        for (String word : words) {
            int hash = hashFunc.apply(word);
            if (hash < 0 || hash >= 16777216) {
                throw new Exception("hash too long for word: " + word + " hash: " + hash);
            }

            if(!hashes.add(hash)) {
                numCollisions++;
                if (collisions.add(hash)) {
                    numCollisions++;
                }
            }
        }