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

Sentence: 'a person riding a camel in front of a truck'. Find frequency of the letter 't'
2

Sentence: 'group of cars on the road with the sun setting behind it'. Find frequency of the letter 'd'
2

Sentence: 'a train on a train track going through a bunch of trees'. Find frequency of the letter 'u'

2