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

### Instruction:
 一个动物园有21只企鹅和两倍于此的北极熊。他们总共有多少只动物？


### Response:
 北极熊：21(2)=42
总共：21+42=<<21+42=63>>63