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

[Q]: Sentence: 'a group of people walking down a rain soaked street with umbrellas'. Find frequency of the letter 'w'
[A]: 3


[Q]: Sentence: 'men standing in the grass with a frisbee'. Find frequency of the letter 'a'
[A]: 3


[Q]: Sentence: 'a traffic light with all green lights over a street'. Find frequency of the letter 'h'
[A]:
3