TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'an commercial airline airplane flies above the clouds'. Find frequency of the letter 'n'

SOLUTION: 3

PROBLEM: Sentence: 'a long row of tables displaying lots of fruit'. Find frequency of the letter 'o'

SOLUTION: 5

PROBLEM: Sentence: 'a bear  that is in the grass in the wild'. Find frequency of the letter 'l'

SOLUTION:
1