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

[EX Q]: Sentence: 'a yellow and green train on a train track in a wooded area'. Find frequency of the letter 'o'
[EX A]: 4

[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 cow being held by its harness in a open field'. Find frequency of the letter 'g'
[EX A]:
1