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

### Instruction:
Nine hundred tickets were sold to a concert. Three-fourths of those who bought the ticket came before the start of the concert. Five-ninths of the remaining came few minutes after the first song. Eighty people arrived during the middle part of the concert while the rest did not go. How many of those who bought the tickets did not go?

### Response:
 900 x 3/4 = <<900*3/4=675>>675 watu walifika kabla ya tamasha kuanza.
900 - 675 = <<900-675=225>>225 watu hawakufika kabla ya tamasha kuanza.
225 x 5/9 = 125 watu walifika dakika chache baada ya wimbo wa kwanza.
Hivyo, 225 - 125 = <<225-125=100>>100 watu walifika wakati wa sehemu ya katikati ya tamasha.
Hivyo, 100 - 80 = <<100-80=20>>20 watu hawakwenda tamasha.