instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a bus is driving on the street behind some cars'. Find frequency of the letter 'a'
answer:
2


question:
Sentence: 'a castle like bed room that has the era of templar knight similarities'. Find frequency of the letter 'm'
answer:
3


question:
Sentence: 'a participant in a male doubles tennis match prepares to reach for the ball'. Find frequency of the letter 'a'
answer:

9