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

### Instruction:
Sonny received 45 boxes of cookies from his friend yesterday. He gave 12 to his brother, 9 to his sister, and he gave 7 to his cousin. How many boxes of cookies were left for him?

### Response:
 Sonny alitoa masanduku 12 + 9 + 7 = <<12+9+7=28>>28 ya biskuti.
Hivyo, alibakiwa na masanduku 45 - 28 = <<45-28=17>>17 ya biskuti.