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

Input: Consider Input: Sentence: 'there is an old stove with old pots on the burners'. Find frequency of the letter 't'

Output: 5


Input: Consider Input: Sentence: 'a group of three dogs laying on a kitchen floor'. Find frequency of the letter 'r'

Output: 3


Input: Consider Input: Sentence: 'a pink, cat-designed microwave is on sale for $69.99 and was originally $91.99'. Find frequency of the letter 'd'


Output: 3