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

[EX Q]: Sentence: 'a man with a large grey and black beard and glasses and a tie'. Find frequency of the letter 'e'
[EX A]: 5

[EX Q]: Sentence: 'the skateboarder has on red and black sneakers and is riding a skateboard'. Find frequency of the letter 'g'
[EX A]: 1

[EX Q]: Sentence: 'a large rock mountain sitting in the middle of the desert'. Find frequency of the letter 't'
[EX A]:
6