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

[Q]: Sentence: 'an old boat on a beach near a large body of water'. Find frequency of the letter 'a'
[A]: 8


[Q]: Sentence: 'a gray airplane with metal petals on the wings takes off from an airport'. Find frequency of the letter 'i'
[A]: 4


[Q]: Sentence: 'a group of people gathered waving flags and watching'. Find frequency of the letter 'e'
[A]:
4