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

[Q]: Sentence: 'a lady mixes some things in a blender as people look on'. Find frequency of the letter 'i'
[A]: 3


[Q]: Sentence: 'a blue train on a track next to another track'. Find frequency of the letter 'c'
[A]: 2


[Q]: Sentence: 'a clock on a building in between two buildings'. Find frequency of the letter 'n'
[A]:
5