instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'two men are playing a video game as another sits watching'. Find frequency of the letter 'a'
answer:
7


question:
Sentence: 'a man skating down a stair rail in front of a bunch of people'. Find frequency of the letter 'o'
answer:
5


question:
Sentence: 'a group of white vases sitting behind a glass window'. Find frequency of the letter 'a'
answer:

4