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

[EX Q]: Sentence: 'a man swinging a bat while playing baseball'. Find frequency of the letter 'm'
[EX A]: 1

[EX Q]: Sentence: 'a person dressed all in black snowboarding down a slope'. Find frequency of the letter 'e'
[EX A]: 4

[EX Q]: Sentence: 'a man on a surfboard riding a wave'. Find frequency of the letter 's'
[EX A]:
1