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

Sentence: 'a group of men standing on the side of a boat'. Find frequency of the letter 'o'
5

Sentence: 'an orange cat sitting on the ground next to a  purse'. Find frequency of the letter 's'
2

Sentence: 'families wait to board the train as it sits on the tracks'. Find frequency of the letter 'i'

6