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

[Q]: Sentence: 'a piece of film shows two street signs crossing each other'. Find frequency of the letter 'f'
[A]: 2


[Q]: Sentence: 'a guy riding a bike close to a car in the street'. Find frequency of the letter 'i'
[A]: 4


[Q]: Sentence: 'a person in ski attire posing under a sign giving directions'. Find frequency of the letter 's'
[A]:
5