Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What is the location attendance of the game with A. Horford (10) as the highest rebounds and J. Johnson (21) as the highest points?

### Inputs:
table_name: table, columns: ['Game', 'Date', 'Team', 'Score', 'High points', 'High rebounds', 'High assists', 'Location Attendance', 'Series']

### Response:
SELECT Location Attendance FROM table WHERE High rebounds = a. horford (10) AND High points = j. johnson (21)