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

[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: 'group of cars on the road with the sun setting behind it'. Find frequency of the letter 'd'
[EX A]: 2

[EX Q]: Sentence: 'two men playing a video game as other look on'. Find frequency of the letter 'h'
[EX A]:
1