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 metallic stove top oven inside of a wooden kitchen'. Find frequency of the letter 'v'
[EX A]: 2

[EX Q]: Sentence: 'there is a couch, bench, and entertainment shelf shown in the living room'. Find frequency of the letter 'i'
[EX A]:
5