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

Example Input: Sentence: 'a couple of kids laying in bed together'. Replace the letter 'o' with 'v' in the sentence.
Example Output: a cvuple vf kids laying in bed tvgether

Example Input: Sentence: 'a toaster oven painted on the side of a wall'. Replace the letter 'e' with 'p' in the sentence.
Example Output: a toastpr ovpn paintpd on thp sidp of a wall

Example Input: Sentence: 'a giraffe standing at the twelve foot mark'. Replace the letter 'a' with 'v' in the sentence.
Example Output:
v girvffe stvnding vt the twelve foot mvrk