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

[EX Q]: Sentence: 'two boys are doing skateboard jumps in the street'. Find frequency of the letter 's'
[EX A]: 4

[EX Q]: Sentence: 'a man opening up a package sitting on a couch'. Find frequency of the letter 'n'
[EX A]: 5

[EX Q]: Sentence: 'a man riding a motorcycle down a road with dogs on the back'. Find frequency of the letter 'c'
[EX A]:
3