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

### Instruction:
What is the model number introduced May 1999?

### Inputs:
table_name: table, columns: ['Model', 'Introduction', 'Discontinued', 'CPU Speed', 'Print resolution (DPI) Resolution is given in dots per inch (DPI)', 'Print speed (PPM)', 'Standard memory', 'Maximum memory']

### Response:
SELECT MAX Model FROM table WHERE Introduction = May 1999