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

Input: Consider Input: Sentence: 'an commercial airline airplane flies above the clouds'. Find frequency of the letter 'n'

Output: 3


Input: Consider Input: Sentence: 'three elephants walk up a dirt trail from the water'. Find frequency of the letter 'l'

Output: 3


Input: Consider Input: Sentence: 'a few people working with colored fabrics in different ways'. Find frequency of the letter 'k'


Output: 1