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

[Q]: Sentence: 'a silver train crossing the road on tracks'. Find frequency of the letter 'r'
[A]: 5


[Q]: Sentence: 'a person holding onto a pink kite at the beach'. Find frequency of the letter 'n'
[A]: 4


[Q]: Sentence: 'a kitchen with a breakfast bar and center island'. Find frequency of the letter 't'
[A]:
4