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

### Instruction:
How many sales had a peak position of 1 and a certification of 6x platinum?

### Inputs:
table_name: table, columns: ['Rank', 'Artist', 'Album', 'Peak position', 'Sales', 'Certification']

### Response:
SELECT COUNT Sales FROM table WHERE Peak position = 1 AND Certification = 6x platinum