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

Sentence: 'older man getting ready to swing his bat at a ball on a stand in front of a group of viewers'. Find frequency of the letter 'n'
7

Sentence: 'a man holding a baseball bat an playing baseball'. Find frequency of the letter 'l'
6

Sentence: 'many airport employees work around a plane on a runway'. Find frequency of the letter 'o'

5