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 young man with glasses on is taking a big bite'. Find frequency of the letter 's'
[EX A]: 4

[EX Q]: Sentence: 'a bunch of ducks on a field with feather all around'. Find frequency of the letter 'b'
[EX A]:
1