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

### Instruction:
 安娜每个三明治放三片火腿。如果她有31片火腿，她还需要多少片火腿才能做50个火腿三明治？


### Response:
 安娜需要3 x 50 = <<3*50=150>>150片火腿来做50个三明治。
安娜还需要150 - 31 = <<150-31=119>>119片火腿。