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

[Q]: Sentence: 'a red building with a crowd of people outside it near the water'. Find frequency of the letter 'e'
[A]: 7


[Q]: Sentence: 'a man riding a skateboard up the side of a ramp'. Find frequency of the letter 'u'
[A]: 1


[Q]: Sentence: 'evening shot of a university library and its shadows'. Find frequency of the letter 'w'
[A]:
1