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

Sentence: 'hand holding a white calculator inside a store'. Find frequency of the letter 'o'
3

Sentence: 'town clocks affixed to a tall, brick building'. Find frequency of the letter 'r'
1

Sentence: 'man is snow gear and skis skiing in the snow'. Find frequency of the letter 'i'

5