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

Sentence: 'a woman throwing a frisbee on a field'. Find frequency of the letter 's'
1

Sentence: 'some food on plates next to each other on a table'. Find frequency of the letter 'e'
6

Sentence: 'a small little toilet that is in a corner'. Find frequency of the letter 'a'
4