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

[EX Q]: Sentence: 'the interior of a living and dining room'. Find frequency of the letter 'i'
[EX A]: 6

[EX Q]: Sentence: 'one man grabbing another at a table while laughing'. Find frequency of the letter 'n'
[EX A]: 5

[EX Q]: Sentence: 'an old fashioned airplane lifting off a field'. Find frequency of the letter 'd'
[EX A]:
3