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

[Q]: Sentence: 'a bus with two floors belonging to london country'. Find frequency of the letter 't'
[A]: 4

[Q]: Sentence: 'a red stop sign with street signs above it'. Find frequency of the letter 't'
[A]: 5

[Q]: Sentence: 'a girl laying on a bed posing for a picture'. Find frequency of the letter 'i'
[A]:
4