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

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

[EX Q]: Sentence: 'a young girl skiing down a snowy mountain'. Find frequency of the letter 'l'
[EX A]: 1

[EX Q]: Sentence: 'a man wearing a white shirt and tie'. Find frequency of the letter 'n'
[EX A]:
3