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

Sentence: 'a cooked pizza on a silver platter with another in the background'. Find frequency of the letter 'e'
5

Sentence: 'a large cooked pizza on a dining table'. Find frequency of the letter 'n'
3

Sentence: 'a man is playing wii tennis in his living room'. Find frequency of the letter 'i'

9