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

[EX Q]: Sentence: 'a tennis player after hitting a shot back to the other side of the court'. Find frequency of the letter 'n'
[EX A]: 3

[EX Q]: Sentence: 'man sitting on the side of a van playing the guitar'. Find frequency of the letter 'm'
[EX A]: 1

[EX Q]: Sentence: 'a small table with a laptop and fancy tea service'. Find frequency of the letter 'e'
[EX A]:
4