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

### Instruction:
What is the average height for hewitt class, with prom less than 86, and a Peak of gragareth?

### Inputs:
table_name: table, columns: ['Peak', 'Height (m)', 'Prom. (m)', 'Class', 'Parent']

### Response:
SELECT AVG Height (m) FROM table WHERE Class = hewitt AND Prom. (m) < 86 AND Peak = gragareth