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

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

[EX Q]: Sentence: 'the skateboarder has on red and black sneakers and is riding a skateboard'. Find frequency of the letter 'g'
[EX A]: 1

[EX Q]: Sentence: 'a baseball game with players in motion, running and reaching'. Find frequency of the letter 'o'
[EX A]:
2