instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a red and white train passing a train station'. Find frequency of the letter 'a'
answer:
7


question:
Sentence: 'a woman fully dressed as a geisha'. Find frequency of the letter 'm'
answer:
1


question:
Sentence: 'a tail of a cat hanging on the outside of a suitcase'. Find frequency of the letter 'c'
answer:

2