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

[Q]: Sentence: 'supplies and tools are arranged on the floor with a hard hat and bag'. Find frequency of the letter 'n'
[A]: 4


[Q]: Sentence: 'an area that has surrounded by a metal fence'. Find frequency of the letter 'o'
[A]: 1


[Q]: Sentence: 'an "eva air" airplane in an airport'. Find frequency of the letter 'r'
[A]:
4