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

[EX Q]: Sentence: 'a man serving himself pizza in a wooden booth'. Find frequency of the letter 'n'
[EX A]: 4

[EX Q]: Sentence: 'a group of people stand inside of a big room'. Find frequency of the letter 'o'
[EX A]: 6

[EX Q]: Sentence: 'two women and three men sitting at a table posing for a picture'. Find frequency of the letter 'g'
[EX A]:
2