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

### Instruction:
A local park has 70 pigeons that call the park home. Half of the pigeons are black, and 20 percent of the black pigeons are male.  How many more black female pigeons are there than black male pigeons?

### Response:
 Njiwa weusi: 70/2=<<70/2=35>>35
Njiwa weusi wa kiume: 35(.20)=7
35-7=<<35-7=28>>28
Kuna njiwa weusi wa kike 28-7=<<28-7=21>>21 zaidi