Table:
Date
Competition
Location
Country
Event
Placing
Rider
Nationality

31 October 2008
2008–09 World Cup
Manchester
United Kingdom
Sprint
1
Victoria Pendleton
GBR

31 October 2008
2008–09 World Cup
Manchester
United Kingdom
Keirin
2
Jason Kenny
GBR

1 November 2008
2008–09 World Cup
Manchester
United Kingdom
Sprint
1
Jason Kenny
GBR

1 November 2008
2008–09 World Cup
Manchester
United Kingdom
500 m time trial
1
Victoria Pendleton
GBR

2 November 2008
2008–09 World Cup
Manchester
United Kingdom
Team sprint
1
Ross Edgar
GBR

2 November 2008
2008–09 World Cup
Manchester
United Kingdom
Team sprint
1
Jason Kenny
GBR

2 November 2008
2008–09 World Cup
Manchester
United Kingdom
Team sprint
1
Jamie Staff
GBR

2 November 2008
2008–09 World Cup
Manchester
United Kingdom
Keirin
1
Victoria Pendleton
GBR

2 November 2008
5th International Keirin Event
Manchester
United Kingdom
International keirin
2
Ross Edgar
GBR

13 February 2009
2008–09 World Cup
Copenhagen
Denmark
Team sprint
1
Chris Hoy
GBR

13 February 2009
2008–09 World Cup
Copenhagen
Denmark
Team sprint
1
Jason Kenny
GBR

13 February 2009
2008–09 World Cup
Copenhagen
Denmark
Team sprint
1
Jamie Staff
GBR

13 February 2009
2008–09 World Cup
Copenhagen
Denmark
Sprint
1
Victoria Pendleton
GBR

30 October 2009
2009–10 World Cup
Manchester
United Kingdom
Keirin
1
Chris Hoy
GBR

30 October 2009
2009–10 World Cup
Manchester
United Kingdom
Sprint
1
Victoria Pendleton
GBR

30 October 2009
2009–10 World Cup
Manchester
United Kingdom
Sprint
1
Chris Hoy
GBR

30 October 2009
2009–10 World Cup
Manchester
United Kingdom
500 m time trial
2
Victoria Pendleton
GBR

1 November 2009
2009–10 World Cup
Manchester
United Kingdom
Team sprint
1
Ross Edgar
GBR

1 November 2009
2009–10 World Cup
Manchester
United Kingdom
Team sprint
1
Chris Hoy
GBR

1 November 2009
2009–10 World Cup
Manchester
United Kingdom
Team sprint
1
Jamie Staff
GBR

Regarding the table displayed, can you identify how many rows and columns it has? Return the result as JSON in the format {"row_number": "m", "column_number": "n"}, e.g., {"row_number": "12", "column_number": "7"}.

This table has 21 rows and 8 columns. Thus, the final answer is {"row_number": "21", "column_number": "8"}.