instruction:
In this task, you need to count the number of times the given letter appears in the given sentence.
question:
Sentence: 'an audience watches as a bird spreads its wings'. Find frequency of the letter 'd'
answer:
3


question:
Sentence: 'a passenger train that is going over a bridge'. Find frequency of the letter 't'
answer:
3


question:
Sentence: 'a piece of pizza with lots of tomatoes'. Find frequency of the letter 's'
answer:

2