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

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: 'three colorful knit bear toys with button eyes'. Replace the letter 'r' with 'z' in the sentence.
Example Output: thzee colozful knit beaz toys with button eyes

Example Input: Sentence: 'a blue and orange subway sits at a station'. Replace the letter 'n' with 'z' in the sentence.
Example Output:
a blue azd orazge subway sits at a statioz