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

[Q]: Sentence: 'people playing wii bowling in a modern library'. Find frequency of the letter 'o'
[A]: 3


[Q]: Sentence: 'a woman in yellow dress standing next to a horse'. Find frequency of the letter 'l'
[A]: 2


[Q]: Sentence: 'a man standing in front of a poster pointing his finger'. Find frequency of the letter 't'
[A]:
4