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

[Q]: Sentence: 'a grey hummingbird by fence and tree branches'. Find frequency of the letter 'y'
[A]: 2


[Q]: Sentence: 'a golden haired dog looking out of an open window'. Find frequency of the letter 'd'
[A]: 4


[Q]: Sentence: 'one, 35 av, 81 st, 35th avenue street signs on one pole'. Find frequency of the letter 'h'
[A]:
1