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

Sentence: 'a glass bowl of raw broccoli, a ceramic bowl of raw green chili peppers, and steel bowl of raw daikon'. Find frequency of the letter 'a'
9

Sentence: 'a chair and umbrella on a sandy beach'. Find frequency of the letter 's'
1

Sentence: 'baked pizza with tomatoes displayed on table for consumption'. Find frequency of the letter 'c'

1