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

[EX Q]: Sentence: 'a blue train on a track next to another track'. Find frequency of the letter 'c'
[EX A]: 2

[EX Q]: Sentence: 'two little girls playing with a bat and a tennis ball'. Find frequency of the letter 'w'
[EX A]: 2

[EX Q]: Sentence: 'a lot of broccoli sitting on a table'. Find frequency of the letter 'n'
[EX A]:
2