instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a silver train crossing the road on tracks'. Find frequency of the letter 'r'
answer:
5


question:
Sentence: 'food sitting in bowls on table with checked tablecloth'. Find frequency of the letter 't'
answer:
6


question:
Sentence: 'several different types of vehicles driving on a busy street'. Find frequency of the letter 't'
answer:

4