instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a log in the water with three birds perched on it'. Find frequency of the letter 'r'
answer:
4

question:
Sentence: 'a lady is standing near a luggage stand at the air port'. Find frequency of the letter 'a'
answer:
9

question:
Sentence: 'a man posing and riding a wave on a surfboard'. Find frequency of the letter 'd'
answer:
3