instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'a double decker bus with a lot of people on board'. Find frequency of the letter 'l'
answer:
3


question:
Sentence: 'a mixed bouquet of flowers in a glass vase set before a window'. Find frequency of the letter 'w'
answer:
3


question:
Sentence: 'a long narrow room with a window at the far end'. Find frequency of the letter 'h'
answer:

2