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

### Instruction:
What is the number for t c (k) when the notation is tl-2212?

### Inputs:
table_name: table, columns: ['Formula', 'Notation', 'T c (K)', 'No. of Cu-O planes in unit cell', 'Crystal structure']

### Response:
SELECT COUNT T c (K) FROM table WHERE Notation = Tl-2212