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

[Q]: Sentence: 'a notebook and pen are left on a park bench'. Find frequency of the letter 'e'
[A]: 5


[Q]: Sentence: 'a long row of tables displaying lots of fruit'. Find frequency of the letter 'o'
[A]: 5


[Q]: Sentence: 'brightly colored blue, yellow and white train coming down tracks near a row of trees'. Find frequency of the letter 'm'
[A]:
1