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

[EX Q]: Sentence: 'a toilet filled with a brown liner and dirty water'. Find frequency of the letter 't'
[EX A]: 5

[EX Q]: Sentence: 'a man walking a large elephant down a dirt road'. Find frequency of the letter 'g'
[EX A]: 2

[EX Q]: Sentence: 'a notebook and pen are left on a park bench'. Find frequency of the letter 'e'
[EX A]:
5