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

[EX Q]: Sentence: 'some people sitting on surfboards in the water'. Find frequency of the letter 't'
[EX A]: 4

[EX Q]: Sentence: 'two giraffes standing next to some trees'. Find frequency of the letter 'f'
[EX A]: 2

[EX Q]: Sentence: 'an older man and woman in the kitchen leaning on the counter'. Find frequency of the letter 'a'
[EX A]:
5