TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a busy intersection with cars moving at night'. Replace the letter 's' with 'f' in the sentence.

SOLUTION: a bufy interfection with carf moving at night

PROBLEM: Sentence: 'a couple of brown bears walking across a lush green field'. Replace the letter 'w' with 'o' in the sentence.

SOLUTION: a couple of broon bears oalking across a lush green field

PROBLEM: Sentence: 'a pizza on a red plate a ith to be served'. Replace the letter 'e' with 'g' in the sentence.

SOLUTION:
a pizza on a rgd platg a ith to bg sgrvgd