TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a couple giraffes walking through a fielded area'. Replace the letter 'e' with 'c' in the sentence.

SOLUTION: a couplc giraffcs walking through a ficldcd arca

PROBLEM: Sentence: 'street signs hanging next to a traffic light on a city street'. Replace the letter 'g' with 'm' in the sentence.

SOLUTION: street simns hanminm next to a traffic limht on a city street

PROBLEM: Sentence: 'a man after he just hit a tennis ball'. Replace the letter 'r' with 'm' in the sentence.

SOLUTION:
a man aftem he just hit a tennis ball