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

[Q]: Sentence: 'a castle like bed room that has the era of templar knight similarities'. Find frequency of the letter 'm'
[A]: 3


[Q]: Sentence: 'a small white plane sitting on top of the ocean'. Find frequency of the letter 'e'
[A]: 4


[Q]: Sentence: 'an old, black truck selling food on street'. Find frequency of the letter 'e'
[A]:
3