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

### Instruction:
How many years Joined have a Size smaller than 417, and an IHSAA Class of A, and a School of jac-cen-del?

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

### Response:
SELECT COUNT Year Joined FROM table WHERE Size < 417 AND IHSAA Class = a AND School = jac-cen-del