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

[Q]: Sentence: 'a crowd of people standing in front of a green train'. Find frequency of the letter 'g'
[A]: 2


[Q]: Sentence: 'an area that has surrounded by a metal fence'. Find frequency of the letter 'o'
[A]: 1


[Q]: Sentence: 'a young boy is being overtaken by a wave while body boarding'. Find frequency of the letter 'b'
[A]:
5