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

[Q]: Sentence: 'two metal  benches on an empty train platform'. Find frequency of the letter 'n'
[A]: 4


[Q]: Sentence: 'a couple of people are sitting at a table'. Find frequency of the letter 'e'
[A]: 5


[Q]: Sentence: 'two metal  benches on an empty train platform'. Find frequency of the letter 'n'
[A]:
4