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

Sentence: 'hotel towels with sunglasses perched and hotel business cards and catalog'. Find frequency of the letter 'o'
4

Sentence: 'an image of a street sign with a corner restaurant'. Find frequency of the letter 'u'
1

Sentence: 'a male in a black coat is holding a black umbrella and people on a street'. Find frequency of the letter 'n'

4