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

Sentence: 'a man hitting a tennis ball with a tennis racquet'. Find frequency of the letter 't'
6

Sentence: 'a bird is perched on a container in a person's hand'. Find frequency of the letter 'c'
2

Sentence: 'two men preparing cakes in the kitchen of a bakery'. Find frequency of the letter 'y'
1