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

[Q]: Sentence: 'this is a sign in front of a large cathedral'. Find frequency of the letter 'a'
[A]: 5


[Q]: Sentence: 'a white toilet sitting next to a bathroom sink'. Find frequency of the letter 'b'
[A]: 1


[Q]: Sentence: 'a woman is taking a sip of a drink from a glass'. Find frequency of the letter 'i'
[A]:
4