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

[EX Q]: Sentence: 'a woman swinging a tennis racquet towards a tennis ball'. Find frequency of the letter 'e'
[EX A]: 3

[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: 'a desktop computer monitor sitting on a desk'. Find frequency of the letter 'e'
[EX A]:
3