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

Sentence: 'a group of people stand inside of a big room'. Find frequency of the letter 'o'
6

Sentence: 'there is a baseball game on and a few people are watching'. Find frequency of the letter 'i'
2

Sentence: 'a wall mounted with honey comb tiles on it'. Find frequency of the letter 'd'

1