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

[Q]: Sentence: 'a birthday cake with a number one and three candle'. Find frequency of the letter 'w'
[A]: 1

[Q]: Sentence: 'a snowboarder making a jump of a snowy ledge'. Find frequency of the letter 'o'
[A]: 4

[Q]: Sentence: 'a set of long tables with various people siting and standing at the tables, with laptop computers in front of them'. Find frequency of the letter 'i'
[A]:
7