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

[EX Q]: Sentence: 'a large group of motorcycles parked along a street'. Find frequency of the letter 'a'
[EX A]: 5

[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: 'a red and black train going on the tracks'. Find frequency of the letter 'c'
[EX A]:
2