instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a group of cars and house on truck passing in a street'. Find frequency of the letter 'i'
answer:
2


question:
Sentence: 'different sets of luggage in a baggage claim area'. Find frequency of the letter 'r'
answer:
2


question:
Sentence: 'a man skating down a stair rail in front of a bunch of people'. Find frequency of the letter 'o'
answer:

5