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

[EX Q]: Sentence: 'a dog has found a rather large stick for playing fetch'. Find frequency of the letter 't'
[EX A]: 3

[EX Q]: Sentence: 'a man paddle boarding by a boat dock in a city'. Find frequency of the letter 'o'
[EX A]: 3

[EX Q]: Sentence: 'the skiers are enjoying the mountain of fresh powder'. Find frequency of the letter 'f'
[EX A]:
2