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

Ex Input:
Sentence: 'silhouette of person playing frisbee with moutain and sunset'. Find frequency of the letter 'i'

Ex Output:
5


Ex Input:
Sentence: 'a room with a big screen television and a couch'. Find frequency of the letter 'h'

Ex Output:
2


Ex Input:
Sentence: 'people on a beach with a kite flying in the air'. Find frequency of the letter 'i'

Ex Output:

5