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

Sentence: 'a train station with a train pulling into the platform'. Find frequency of the letter 'i'
6

Sentence: 'the skateboarder is jumping over a huge statue of a shoe'. Find frequency of the letter 'i'
2

Sentence: 'some red white yellow and blue buses and some buildings'. Find frequency of the letter 'e'

7