instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a gray airplane with metal petals on the wings takes off from an airport'. Find frequency of the letter 'i'
answer:
4


question:
Sentence: 'a toilet of some sort near a sink of some sort'. Find frequency of the letter 'o'
answer:
7


question:
Sentence: 'a car has been packed full of suitcases'. Find frequency of the letter 't'
answer:

1