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

[EX Q]: Sentence: 'a bus is stopped in front of a graphic statue'. Find frequency of the letter 'e'
[EX A]: 2

[EX Q]: Sentence: 'an airplane is being towed away from the jet bridge'. Find frequency of the letter 's'
[EX A]: 1

[EX Q]: Sentence: 'a baseball batter is getting ready to hit the ball'. Find frequency of the letter 'y'
[EX A]:
1