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

[EX Q]: Sentence: 'large grassy pasture filled with trees and a single horse'. Find frequency of the letter 'l'
[EX A]: 4

[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 tennis player bounces a tennis ball during a match'. Find frequency of the letter 'g'
[EX A]:
1