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

Sentence: 'a white and blue plate topped with meat and a salad'. Find frequency of the letter 'u'
1

Sentence: 'a passenger bus that is driving down the street'. Find frequency of the letter 'r'
3

Sentence: 'a dog sitting next to a double seated red bicycle'. Find frequency of the letter 'e'

6