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

### Instruction:
When 20 is the rr4 points what is the lowest rr3 points?

### Inputs:
table_name: table, columns: ['Team name', 'Races', 'Won', 'RR1 Pts.', 'RR2 Pts.', 'RR3 Pts.', 'RR4 Pts.', 'Total Pts.', 'Ranking']

### Response:
SELECT MIN RR3 Pts. FROM table WHERE RR4 Pts. = 20