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

Sentence: 'a bus with two floors belonging to london country'. Find frequency of the letter 't'
4

Sentence: 'two baseball players high five each other during a game'. Find frequency of the letter 'y'
1

Sentence: 'a kitchen with a pile of boxes to be unpacked'. Find frequency of the letter 'e'

5