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

### Instruction:
How many numbers have sp of 20/1 and a finishing position of fence 19?

### Inputs:
table_name: table, columns: ['SP', 'Number', 'Horse', 'Age', 'Handicap (st-lb)', 'Jockey', 'Trainer', 'Owner', 'Colours', 'Finishing position']

### Response:
SELECT COUNT Number FROM table WHERE SP = 20/1 AND Finishing position = Fence 19