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

[Q]: Sentence: 'a bunch of cows that are in the field'. Find frequency of the letter 'a'
[A]: 3


[Q]: Sentence: 'salad and vegetables with me on top of plate'. Find frequency of the letter 'o'
[A]: 3


[Q]: Sentence: 'a group of people that are running in the street'. Find frequency of the letter 'u'
[A]:
2