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

### Instruction:
How many were the viewers (in millions) of the series no. 45?

### Inputs:
table_name: table, columns: ['Episode No.', 'Series No.', 'Episode', 'Director', 'Writer(s)', 'Original airdate', 'Viewers (millions)']

### Response:
SELECT Viewers (millions) FROM table WHERE Series No. = 45