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

[EX Q]: Sentence: 'two men in black wet suits beside a white surfboard'. Find frequency of the letter 'e'
[EX A]: 5

[EX Q]: Sentence: 'person wearing all white leaned up against a wall with a yellow sign'. Find frequency of the letter 'a'
[EX A]: 8

[EX Q]: Sentence: 'two fake dogs sit in front of a building'. Find frequency of the letter 's'
[EX A]:
2