private void printDirectReplies( Long parentId ) throws IOException {

        convFileWriter.write(parentId.toString());

        if( !adjacencyList.containsKey(parentId))
            return;

        long numOfReplies = adjacencyList.get(parentId).size();

        if(numOfReplies == 0)
            return;

        convFileWriter.write('(');

        for( Long childId: adjacencyList.get(parentId)) {

            printDirectReplies(childId);

            if( numOfReplies > 1 )
                convFileWriter.write(',');

            numOfReplies--;
        }
        convFileWriter.write(')');
    }