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

[EX Q]: Sentence: 'a girl hitting a tennis ball on a court'. Find frequency of the letter 'l'
[EX A]: 3

[EX Q]: Sentence: 'the skateboarder has on red and black sneakers and is riding a skateboard'. Find frequency of the letter 'g'
[EX A]: 1

[EX Q]: Sentence: 'a clock tower that has two clocks sits in the middle of a sky light'. Find frequency of the letter 'l'
[EX A]:
4