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

Sentence: 'statues of 2 zebras and 1 giraffe in a doorway'. Find frequency of the letter 'a'
6

Sentence: 'a person on a skateboard going down a ramp'. Find frequency of the letter 'n'
4

Sentence: 'a horse and two giraffes in a sanctuary'. Find frequency of the letter 't'

2