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

Ex Input:
Sentence: 'a double decker transit bus parks by a blue on the side of the street in front of a brick building in the city'. Find frequency of the letter 't'

Ex Output:
9


Ex Input:
Sentence: 'two little girls playing with a bat and a tennis ball'. Find frequency of the letter 'w'

Ex Output:
2


Ex Input:
Sentence: 'a woman sitting in the sand on the beach with different items'. Find frequency of the letter 'i'

Ex Output:

6