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

### Instruction:
 肖娜的锻炼目标是做30个仰卧起坐。星期一，肖娜只能做12个仰卧起坐，所以她决定在星期二弥补剩下的。然而，她在星期二只能做19个仰卧起坐。为了达到她的最低目标并弥补她没做的那些，肖娜在星期三应该做多少个仰卧起坐？


### Response:
 星期一，肖娜少做了30 - 12 = <<30-12=18>>18个仰卧起坐
星期二，肖娜少做了30 - 19 = 11个仰卧起坐
星期三，肖娜需要做30 + 18 + 11 = <<30+18+11=59>>59个仰卧起坐