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

Example Input: Sentence: 'busy city street with pedestrians and cars with lights all around'. Replace the letter 'r' with 'k' in the sentence.
Example Output: busy city stkeet with pedestkians and caks with lights all akound

Example Input: Sentence: 'children trying little hamburgers from a tray at school'. Replace the letter 'y' with 'l' in the sentence.
Example Output: children trling little hamburgers from a tral at school

Example Input: Sentence: 'an all white room in an institution with a hospital bed'. Replace the letter 'u' with 'd' in the sentence.
Example Output:
an all white room in an institdtion with a hospital bed