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

Sentence: 'a woman swinging a tennis racquet towards a tennis ball'. Find frequency of the letter 'e'
3

Sentence: 'a child sitting a table with a pizza in front of him'. Find frequency of the letter 'h'
3

Sentence: 'small bedroom with a bed, lamp, dresser, and a small chair'. Find frequency of the letter 'n'
1