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

[EX Q]: Sentence: 'a traffic signal by a wire filled with some birds'. Find frequency of the letter 'e'
[EX A]: 3

[EX Q]: Sentence: 'a baby elephant walks beside an adult elephant along a post and cable'. Find frequency of the letter 'l'
[EX A]: 6

[EX Q]: Sentence: 'a woman wearing a pair of skis'. Find frequency of the letter 'n'
[EX A]:
2