instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a railroad train pulling up to the train platform'. Find frequency of the letter 'o'
answer:
3

question:
Sentence: 'a double decker transit bus parks by a blue on the side of the street in front of a brick building in the city'. Find frequency of the letter 't'
answer:
9

question:
Sentence: 'a grey and white cat lounging atop an open laptop'. Find frequency of the letter 'i'
answer:
2