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

[EX Q]: Sentence: 'an elephant with broken tusks stands in front of a hill and boulders'. Find frequency of the letter 'n'
[EX A]: 7

[EX Q]: Sentence: 'a burning wood stove has a tea pot sitting on top of it and is full of wood'. Find frequency of the letter 'a'
[EX A]: 5

[EX Q]: Sentence: 'a lady covering her mouth sitting by some flowers'. Find frequency of the letter 'l'
[EX A]:
2