TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a open entrance leading to a set of closed doors'. Replace the letter 'd' with 'f' in the sentence.

SOLUTION: a open entrance leafing to a set of closef foors

PROBLEM: Sentence: 'bus with sheep decals in foreign language and doughnuts'. Replace the letter 'g' with 'i' in the sentence.

SOLUTION: bus with sheep decals in foreiin laniuaie and douihnuts

PROBLEM: Sentence: 'a man and his young daughter riding on the back of an elephant'. Replace the letter 'h' with 'r' in the sentence.

SOLUTION:
a man and ris young daugrter riding on tre back of an eleprant