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

[Q]: Sentence: 'a woman standing in front of a bathroom sink in front of a mirror'. Find frequency of the letter 'o'
[A]: 8


[Q]: Sentence: 'a white bowl filled with peeled orange slices'. Find frequency of the letter 's'
[A]: 2


[Q]: Sentence: 'two men are playing a video game as another sits watching'. Find frequency of the letter 'a'
[A]:
7