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

[Q]: Sentence: 'man sitting on the side of a van playing the guitar'. Find frequency of the letter 'm'
[A]: 1

[Q]: Sentence: 'a dog laying on the back of a boat in the water'. Find frequency of the letter 't'
[A]: 4

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