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

[Q]: Sentence: 'a man standing in front of a statue near a metal pole'. Find frequency of the letter 'f'
[A]: 2


[Q]: Sentence: 'a red fire hydrant opened and spilling water'. Find frequency of the letter 'd'
[A]: 4


[Q]: Sentence: 'a surfboard is above a door and under a window'. Find frequency of the letter 'u'
[A]:
2