In this task, you need to count the number of times the given letter appears in the given sentence.

Q: Sentence: 'a blue tripocal bird is perched on a wooden fence'. Find frequency of the letter 'd'

A: 3
****
Q: Sentence: 'there is an old stove with old pots on the burners'. Find frequency of the letter 't'

A: 5
****
Q: Sentence: 'a train passing under a bridge in the middle of a field'. Find frequency of the letter 'r'

A:
3
****