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

Sentence: 'a man in a sweatshirt is taking his own picture'. Find frequency of the letter 'u'
1

Sentence: 'a man sitting in front of a laptop computer next to a child'. Find frequency of the letter 'e'
2

Sentence: 'a red motorcycle is next to a white house'. Find frequency of the letter 'h'

2