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

Example Input: Sentence: 'lots of luggage is jammed into the back compartment of a van'. Replace the letter 'o' with 'h' in the sentence.
Example Output: lhts hf luggage is jammed inth the back chmpartment hf a van

Example Input: Sentence: 'a couple of brown bears walking across a lush green field'. Replace the letter 'w' with 'o' in the sentence.
Example Output: a couple of broon bears oalking across a lush green field

Example Input: Sentence: 'a basket holds flowers, twigs, and various fruits'. Replace the letter 'a' with 'g' in the sentence.
Example Output:
g bgsket holds flowers, twigs, gnd vgrious fruits