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

[EX Q]: Sentence: 'a cat that is standing next to an open suitcase'. Find frequency of the letter 'e'
[EX A]: 3

[EX Q]: Sentence: 'flower in a vase full of water sitting on a stand '. Find frequency of the letter 'l'
[EX A]: 3

[EX Q]: Sentence: 'a baseball player holding a bat on top of a field'. Find frequency of the letter 't'
[EX A]:
2