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

[Q]: Sentence: 'soccer players on opposite teams fight for control over a ball'. Find frequency of the letter 't'
[A]: 4

[Q]: Sentence: 'a couple of boys in a field playing baseball'. Find frequency of the letter 'i'
[A]: 3

[Q]: Sentence: 'the counter of a doctor's office, including a laptop, cotton swabs, and tongue depressors'. Find frequency of the letter 'g'
[A]:
2