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

[Q]: Sentence: 'a white toilet sitting next to a toilet paper roller'. Find frequency of the letter 'o'
[A]: 4


[Q]: Sentence: 'two bigger elephants standing with a small elephant'. Find frequency of the letter 't'
[A]: 5


[Q]: Sentence: 'a person taking a picture of someone else with a phone'. Find frequency of the letter 'n'
[A]:
4