Below is an instruction that describes a task. Write a response that appropriately completes the request in Thai. Please answer in Thai.

### Instruction:
Lizzie has half as many crayons as Bobbie. Bobbie has three times as many crayons as Billie. If Billie has 18 crayons, how many crayons does Lizzie have?

### Response:
 บ็อบบี้มีดินสอ 18 * 3 = <<18*3=54>>54 ดินสอ
ลิซซี่มีดินสอ 54 * 1/2 = <<54*1/2=27>>27 ดินสอ