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

Example Input: Sentence: 'a teddy bear playing a drum and a teddy bear playing a guitar'. Replace the letter 'd' with 'm' in the sentence.
Example Output: a temmy bear playing a mrum anm a temmy bear playing a guitar

Example Input: Sentence: 'many street signs in front of a building while it is snowing'. Replace the letter 'r' with 'x' in the sentence.
Example Output: many stxeet signs in fxont of a building while it is snowing

Example Input: Sentence: 'a man making a call in order to a restaurant'. Replace the letter 's' with 'r' in the sentence.
Example Output:
a man making a call in order to a rertaurant