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

Ex Input:
Sentence: 'a blue and white train is coming down some tracks'. Replace the letter 'b' with 'u' in the sentence.

Ex Output:
a ulue and white train is coming down some tracks

Ex Input:
Sentence: 'a woman gives a thumbs up sign while sitting in front of a sandwich'. Replace the letter 's' with 'h' in the sentence.

Ex Output:
a woman giveh a thumbh up hign while hitting in front of a handwich

Ex Input:
Sentence: 'numbered row boats lined up along a small dock'. Replace the letter 'l' with 'n' in the sentence.

Ex Output:
numbered row boats nined up anong a smann dock