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

### Instruction:
What's the size of Centerville in 89 Wayne county with an IHSAA class of AA in the year before 1974?

### Inputs:
table_name: table, columns: ['School', 'Location', 'Mascot', 'Size', 'IHSAA Class', '# / County', 'Year Joined', 'Previous Conference']

### Response:
SELECT Size FROM table WHERE Year Joined < 1974 AND IHSAA Class = aa AND # / County = 89 wayne AND School = centerville