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

Example Input: Sentence: 'a white bathroom with a stand alone sink and a shower curtain'. Replace the letter 'a' with 'm' in the sentence.
Example Output: m white bmthroom with m stmnd mlone sink mnd m shower curtmin

Example Input: Sentence: 'you are never to old to play with the nintendo wii'. Replace the letter 'e' with 'v' in the sentence.
Example Output: you arv nvvvr to old to play with thv nintvndo wii

Example Input: Sentence: 'a group of cows are grazing on the grass'. Replace the letter 'o' with 'j' in the sentence.
Example Output:
a grjup jf cjws are grazing jn the grass