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

[Q]: Sentence: 'a train going over a bridge with some buildings in the background'. Find frequency of the letter 'd'
[A]: 3


[Q]: Sentence: 'a woman fully dressed as a geisha'. Find frequency of the letter 'm'
[A]: 1


[Q]: Sentence: 'three birds are sitting on a tree in a forest'. Find frequency of the letter 'h'
[A]:
1