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

Example Input: Sentence: 'a man that is on the back of an elephant'. Replace the letter 'c' with 'd' in the sentence.
Example Output: a man that is on the badk of an elephant

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 stop sign and a red fire hydrant grass cars and trees'. Replace the letter 'd' with 's' in the sentence.
Example Output:
a stop sign ans a res fire hysrant grass cars ans trees