In this task, you need to count the number of times the given letter appears in the given sentence.

Sentence: 'a plastic container next to a toilet on a wooden box'. Find frequency of the letter 'i'
3

Sentence: 'a red building with a crowd of people outside it near the water'. Find frequency of the letter 'e'
7

Sentence: 'a small compact car parked in an alley with a bull dog sitting on top of it'. Find frequency of the letter 'i'

5