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

Sentence: 'a softball player holding the bat on first base'. Find frequency of the letter 't'
4

Sentence: 'an commercial airline airplane flies above the clouds'. Find frequency of the letter 'n'
3

Sentence: 'a close up of the photographers plate with the half eaten lunch'. Find frequency of the letter 'a'

5