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

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 man on the news, watched on the television'. Replace the letter 'o' with 'z' in the sentence.
Example Output: a man zn the news, watched zn the televisizn

Example Input: Sentence: 'a bunch of people at a very big table with some pizza'. Replace the letter 'm' with 'l' in the sentence.
Example Output:
a bunch of people at a very big table with sole pizza