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

[EX Q]: Sentence: 'a commuter bus in england by a clock tower building'. Find frequency of the letter 'w'
[EX A]: 1

[EX Q]: Sentence: 'a large cooked pizza on a dining table'. Find frequency of the letter 'n'
[EX A]: 3

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