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

[Q]: Sentence: 'a girl sits on a surfboard and smiles'. Find frequency of the letter 'i'
[A]: 3


[Q]: Sentence: 'a woman holds the reins of a saddled horse'. Find frequency of the letter 'm'
[A]: 1


[Q]: Sentence: 'two giraffes are standing and staring on the inside of a fenced zoo yard'. Find frequency of the letter 'y'
[A]:
1