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

[EX Q]: Sentence: 'a green bus driving in a street filled with heavy traffic'. Find frequency of the letter 'v'
[EX A]: 2

[EX Q]: Sentence: 'there is a person standing on a blue towel'. Find frequency of the letter 'n'
[EX A]: 4

[EX Q]: Sentence: 'baked pizza with tomatoes displayed on table for consumption'. Find frequency of the letter 'c'
[EX A]:
1