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

[EX Q]: Sentence: 'a man in a black shirt prepares to catch a frisbee'. Find frequency of the letter 'f'
[EX A]: 1

[EX Q]: Sentence: 'there is an old stove with old pots on the burners'. Find frequency of the letter 't'
[EX A]: 5

[EX Q]: Sentence: 'a plane is close to landing at an airport'. Find frequency of the letter 't'
[EX A]:
3