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

[Q]: Sentence: 'the receipts from a meal at a restaurant are for  a sandwich, chili, and apple'. Find frequency of the letter 'u'
[A]: 1


[Q]: Sentence: 'a piece of film shows two street signs crossing each other'. Find frequency of the letter 'f'
[A]: 2


[Q]: Sentence: 'a person on skis is travelling through the forest'. Find frequency of the letter 'r'
[A]:
4