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

### Instruction:
How many combination classifications have the winner as Erik Zabel and a points classification as Alessandro Petacchi

### Inputs:
table_name: table, columns: ['Stage', 'Winner', 'General classification', 'Points classification', 'Mountains classification', 'Combination classification', 'Team classification']

### Response:
SELECT COUNT Combination classification FROM table WHERE Points classification = Alessandro Petacchi AND Winner = Erik Zabel