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: 'two computers and a laptop set up on a desk'. Find frequency of the letter 'r'
[EX A]: 1

[EX Q]: Sentence: 'a baby and man sitting at a wood table with four doughnuts'. Find frequency of the letter 'e'
[EX A]:
1