TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a yellow fire hydrant sitting on the sidewalk'. Replace the letter 'o' with 'd' in the sentence.

SOLUTION: a yelldw fire hydrant sitting dn the sidewalk

PROBLEM: Sentence: 'a sign sitting on the side of a snow covered slope'. Replace the letter 'e' with 'g' in the sentence.

SOLUTION: a sign sitting on thg sidg of a snow covgrgd slopg

PROBLEM: Sentence: 'a public official helping to feed some school children a healthy lunch'. Replace the letter 'i' with 't' in the sentence.

SOLUTION:
a publtc offtctal helptng to feed some school chtldren a healthy lunch