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

[Q]: Sentence: 'a bird outside standing on a table looking up'. Find frequency of the letter 'b'
[A]: 2


[Q]: Sentence: 'a dog laying on the back of a boat in the water'. Find frequency of the letter 't'
[A]: 4


[Q]: Sentence: 'a street sign on a white lamp post says ellis'. Find frequency of the letter 'y'
[A]:
1