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

Ex Input:
Sentence: 'two laptop computers sitting on top of a white table'. Find frequency of the letter 'f'

Ex Output:
1


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

Ex Output:
5


Ex Input:
Sentence: 'two middle-aged friends play a wii at home'. Find frequency of the letter 't'

Ex Output:

2