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 costume talking on a cell phone'. Find frequency of the letter 'm'
[EX A]: 2

[EX Q]: Sentence: 'two women standing next to each other holding tennis rackets'. Find frequency of the letter 't'
[EX A]: 7

[EX Q]: Sentence: 'a bathroom has several items next to a sink and on top of a medicine cabinet with a door opened up against a glass-walled shower'. Find frequency of the letter 'a'
[EX A]:
14