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

### Instruction:
 南希有一个装有22个玉米饼片的袋子。她给了她的弟弟7个玉米饼片，给了她的妹妹5个玉米饼片，剩下的她自己留着。南希自己留下了多少个？


### Response:
 在给她的弟弟或妹妹之前的玉米饼片数量是22 - 7 - 5 = <<22-7-5=10>>10个。
所以，南希自己留下了10个。