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

[Q]: Sentence: 'a person on a surfboard in the surf of a wave'. Find frequency of the letter 's'
[A]: 3

[Q]: Sentence: 'a woman holds a wine glass upside down while wearing rabbit ears and staring at a bottle of wine'. Find frequency of the letter 'a'
[A]: 11

[Q]: Sentence: 'man standing beside a part custom motorcycle'. Find frequency of the letter 't'
[A]:
4