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: 'older man getting ready to swing his bat at a ball on a stand in front of a group of viewers'. Find frequency of the letter 'n'
[EX A]: 7

[EX Q]: Sentence: 'a red light at a stop in front of some trees'. Find frequency of the letter 'd'
[EX A]:
1