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

[Q]: Sentence: 'a view from a bathroom shows an open door'. Find frequency of the letter 'o'
[A]: 7


[Q]: Sentence: 'a man flying through the air on a bicycle'. Find frequency of the letter 'u'
[A]: 1


[Q]: Sentence: 'tattered and soiled toy bear on a city sidewalk at night'. Find frequency of the letter 'b'
[A]:
1