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

[EX Q]: Sentence: 'a woman holds some baked goods at the convention'. Find frequency of the letter 'd'
[EX A]: 3

[EX Q]: Sentence: 'a picture of two men on a motorcycle in front of a railroad track'. Find frequency of the letter 'n'
[EX A]: 4

[EX Q]: Sentence: 'a couple zebras are standing in a flooded plain '. Find frequency of the letter 'a'
[EX A]:
6