TASK DEFINITION: In this task, you need to count the number of times the given letter appears in the given sentence.
PROBLEM: Sentence: 'a group of cars and house on truck passing in a street'. Find frequency of the letter 'i'

SOLUTION: 2

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

SOLUTION: 5

PROBLEM: Sentence: 'an elephant playing with a white ball'. Find frequency of the letter 'l'

SOLUTION:
4