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

Sentence: 'wooden and black bench on the side of the road'. Find frequency of the letter 'a'
3

Sentence: 'a bowl of vegetables in a soup like substance next to a spoon'. Find frequency of the letter 'a'
5

Sentence: 'man riding a skate board down the little board way'. Find frequency of the letter 'k'

1