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

### Instruction:
How many original air dates were there for episodes with a production code of 4398016?

### Inputs:
table_name: table, columns: ['No in Series', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code', 'U.S. viewers (millions)']

### Response:
SELECT COUNT Original air date FROM table WHERE Production code = 4398016