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

[Q]: Sentence: 'a large grass pasture land with sheep grazing on grass'. Find frequency of the letter 'a'
[A]: 7


[Q]: Sentence: 'a man with a skateboard that is in the street'. Find frequency of the letter 'o'
[A]: 1


[Q]: Sentence: 'a young person stretching using a wii controller looking at the tv in a living room'. Find frequency of the letter 'i'
[A]:
8