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

[Q]: Sentence: 'a woman is looking at sheep off in a field'. Find frequency of the letter 'm'
[A]: 1


[Q]: Sentence: 'two people wearing snowboards sitting on a snowy slope'. Find frequency of the letter 's'
[A]: 5


[Q]: Sentence: 'a cat resting inside of a dish tray in the sink'. Find frequency of the letter 'e'
[A]:
3