int bfsCount(Map<String, List<String>> graph, String startingValue,
             String endingValue) {
    Map<String, Boolean> seenMap = new HashMap<String, Boolean>();
    Iterator<String> keysI = graph.keySet().iterator();
    // initialize a map indicating whether a word has been visited, ie
    // part of the transformation sequence
    while(keysI.hasNext()) {
        String key = keysI.next();
        seenMap.put(key, false);
    }

    // queue to manager this BFS
    Queue<String> q = new LinkedList<String>();
    // enqueue
    q.offer(startingValue);
    seenMap.put(startingValue, true);
    System.out.println(startingValue);

    // similar to tree BFS but we only add unseen children(edges) to the queue
    int count = 1;
    while(!q.isEmpty()) {
        // dequeue
        String head = q.poll();
        List<String> neighbors = graph.get(head);

        for (String neighbor: neighbors) {
            boolean visitedVertex = seenMap.get(neighbor);
            if (!visitedVertex) {
                count++;
                q.offer(neighbor);
                seenMap.put(neighbor, true);
                System.out.println(neighbor);

                if (neighbor.equals(endingValue)) {
                    return count;
                }
            }
        }
    }
    return count;
}