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

### Instruction:
 Xavier anahitaji sahani za karatasi 84 kwa ajili ya sherehe ya kufungua nyumba. Tayari ana sahani 21 za kijani na sahani 28 za nyekundu. Anapaswa kununua sahani ngapi zaidi?


### Response:
 Jumla ya sahani za kijani na nyekundu ni 28 + 21 = <<28+21=49>>49.
Xavier anahitaji 84 - 49 = 35 sahani zaidi.