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

[Q]: Sentence: 'a group of giraffes walk together by a hill'. Find frequency of the letter 'b'
[A]: 1


[Q]: Sentence: 'a person riding a skate board on a city street'. Find frequency of the letter 'a'
[A]: 5


[Q]: Sentence: 'an individual wearing snow skies poses on a snowy terrain'. Find frequency of the letter 'e'
[A]:
4