instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'two bears swim in a blue pool of water'. Find frequency of the letter 'o'
answer:
4


question:
Sentence: 'a person riding a surfboard in the middle of a wave'. Find frequency of the letter 'o'
answer:
3


question:
Sentence: 'a small boy on a skateboard on the road'. Find frequency of the letter 't'
answer:

2