TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a group of people walking along a dirty snow covered road'. Replace the letter 'n' with 'i' in the sentence.

SOLUTION: a group of people walkiig aloig a dirty siow covered road

PROBLEM: Sentence: 'a memorial with various plaques and american flags on it'. Replace the letter 'a' with 'k' in the sentence.

SOLUTION: k memorikl with vkrious plkques knd kmerickn flkgs on it

PROBLEM: Sentence: 'a man standing beside a stopped santa fe train'. Replace the letter 'o' with 'm' in the sentence.

SOLUTION:
a man standing beside a stmpped santa fe train