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

### 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:
Bobbie has 18*3=<<18*3=54>>54 crayons.
Lizzie has 54/2=<<54/2=27>>27 crayons.
#### 27