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: 'the small black and white dog holds onto a frisbee'. Find frequency of the letter 'h'
[A]: 3


[Q]: Sentence: 'two birds watching a boat in the lake moving'. Find frequency of the letter 'g'
[A]:
2