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

[EX Q]: Sentence: 'a number of small boats on a beach near an umbrella'. Find frequency of the letter 's'
[EX A]: 2

[EX Q]: Sentence: 'a woman standing in front of a bathroom sink in front of a mirror'. Find frequency of the letter 'o'
[EX A]: 8

[EX Q]: Sentence: 'a plane that is flying in the sky'. Find frequency of the letter 'i'
[EX A]:
3