instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a toasted sub sandwich is next to a salad'. Find frequency of the letter 'a'
answer:
6


question:
Sentence: 'a lady mixes some things in a blender as people look on'. Find frequency of the letter 'i'
answer:
3


question:
Sentence: 'a person working at an airport, outside of an airplane'. Find frequency of the letter 'r'
answer:

5