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

[Q]: Sentence: 'a silver train crossing the road on tracks'. Find frequency of the letter 'r'
[A]: 5


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


[Q]: Sentence: 'two hot dogs on a plate with beans and coleslaw'. Find frequency of the letter 'g'
[A]:
1