TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a teddy bear playing a drum and a teddy bear playing a guitar'. Replace the letter 'd' with 'm' in the sentence.

SOLUTION: a temmy bear playing a mrum anm a temmy bear playing a guitar

PROBLEM: Sentence: 'some brown black and white horses clouds and rocks'. Replace the letter 'a' with 'n' in the sentence.

SOLUTION: some brown blnck nnd white horses clouds nnd rocks

PROBLEM: Sentence: 'a man sitting on the beach next to a surfboard'. Replace the letter 'g' with 'i' in the sentence.

SOLUTION:
a man sittini on the beach next to a surfboard