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

Example Input: Sentence: 'a yellow street sign sitting on the side of a road'. Replace the letter 'a' with 'd' in the sentence.
Example Output: d yellow street sign sitting on the side of d rodd

Example Input: Sentence: 'a street side tree is filled with candles, teddy bears and balloons'. Replace the letter 'e' with 'c' in the sentence.
Example Output: a strcct sidc trcc is fillcd with candlcs, tcddy bcars and balloons

Example Input: Sentence: 'a man is on skis with his dog next to him'. Replace the letter 'w' with 'f' in the sentence.
Example Output:
a man is on skis fith his dog next to him