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

Sentence: 'a mixed bouquet of flowers in a glass vase set before a window'. Find frequency of the letter 'w'
3

Sentence: 'a dog sitting in the back of a truck flat bed'. Find frequency of the letter 'h'
1

Sentence: 'a vehicle trailing an airplane on a tarmac'. Find frequency of the letter 't'

2