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

[EX Q]: Sentence: 'two zebras feed on a plant through some wire mesh'. Find frequency of the letter 'o'
[EX A]: 4

[EX Q]: Sentence: 'a toasted sub sandwich is next to a salad'. Find frequency of the letter 'a'
[EX A]: 6

[EX Q]: Sentence: 'a woman holding a doughnut in front of her face'. Find frequency of the letter 'l'
[EX A]:
1