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:
|  | Total number of shares purchased (a)(b) | Average price paid per share (b)(c) | Total number of shares purchased as part of publicly announced plans or programs (a) | Approximate dollar value of shares that may yet be purchased under the plans or programs (in millions) (a) |
| --- | --- | --- | --- | --- |
| October 2017 | 2,852,917 | $59.59 | 2,852,917 | $383 |
| November 2017 | 5,342,435 | 58.93 | 5,342,435 | 68 |
| December 2017 | 1,084,498 | 63.06 | 1,084,498 | 3,000 |
| Total | 9,279,850 |  | 9,279,850 |  |
Question:
As of December 2017, how many shares of United Airlines have been purchased?
Answer:
1,084,498