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

[Q]: Sentence: 'two men in black wet suits beside a white surfboard'. Find frequency of the letter 'e'
[A]: 5


[Q]: Sentence: 'young boy flying kite in large field at outdoor event'. Find frequency of the letter 'y'
[A]: 3


[Q]: Sentence: 'a metallic oven stove top under a microwave oven'. Find frequency of the letter 'm'
[A]:
2