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

Example Input: Sentence: 'the big sandwich features several different  colorful ingredients'. Replace the letter 'e' with 'o' in the sentence.
Example Output: tho big sandwich foaturos sovoral difforont  colorful ingrodionts

Example Input: Sentence: 'a baseball player holding a baseball bat during a baseball game'. Replace the letter 'a' with 'u' in the sentence.
Example Output: u busebull pluyer holding u busebull but during u busebull gume

Example Input: Sentence: 'a small cute cat sitting in the bathroom sink'. Replace the letter 'i' with 'u' in the sentence.
Example Output:
a small cute cat suttung un the bathroom sunk