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

[EX Q]: Sentence: 'a red building with a crowd of people outside it near the water'. Find frequency of the letter 'e'
[EX A]: 7

[EX Q]: Sentence: 'a man that is on his cell phone'. Find frequency of the letter 's'
[EX A]: 2

[EX Q]: Sentence: 'a man and woman look inside of a oven'. Find frequency of the letter 'w'
[EX A]:
1