Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Class | Name | Company | Residence | Term Expires Dec 31 | Notes |
| --- | --- | --- | --- | --- | --- |
| A | Max T. Wake | Jones National Bank & Trust Co. | Seward, Nebraska | 2013 |  |
| A | Vacancy |  |  | 2014 |  |
| A | David W. Brownback | Citizens State Bank & Trust Company | Ellsworth, Kansas | 2015 |  |
| B | Vacancy |  |  | 2013 |  |
| B | Richard K. Ratcliffe | Ratcliffe's Inc. | Weatherford, Oklahoma | 2014 |  |
| B | John T. Stout, Jr. | Plaza Belmont Management Group LLC | Shawnee Mission, Kansas | 2015 |  |
| C | Rose Washington | OTulsa Economic Development Corporation | Tulsa, Oklahoma | 2013 |  |
| C | Barbara Mowry | GoreCreek Advisors | Greenwood Village, Colorado | 2014 | Chairman |
| C | Steve Maestas | NAI Maestas and Ward | Albuquerque, New Mexico | 2015 | Deputy Chairman |
Question:
what is the total number of different classes?
Answer:
3