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

[EX Q]: Sentence: 'a crowd of people skiing and enjoying the snow'. Find frequency of the letter 'o'
[EX A]: 5

[EX Q]: Sentence: 'a silver train crossing the road on tracks'. Find frequency of the letter 'r'
[EX A]: 5

[EX Q]: Sentence: 'a giraffe feeding out of a bin in a pen'. Find frequency of the letter 'g'
[EX A]:
2