In this task, you need to replace a letter in the sentence with another given letter.

Sentence: 'a open entrance leading to a set of closed doors'. Replace the letter 'd' with 'f' in the sentence.
a open entrance leafing to a set of closef foors

Sentence: 'a man sitting in a chair with a laptop in his lap'. Replace the letter 'p' with 'v' in the sentence.
a man sitting in a chair with a lavtov in his lav

Sentence: 'a train moves along a quiet railroad track'. Replace the letter 'i' with 'a' in the sentence.

a traan moves along a quaet raalroad track