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

Ex Input:
Sentence: 'a gray and white cat sleeping on top of a laptop computer'. Replace the letter 'l' with 'g' in the sentence.

Ex Output:
a gray and white cat sgeeping on top of a gaptop computer

Ex Input:
Sentence: 'horses drink and graze the field and water'. Replace the letter 'i' with 'c' in the sentence.

Ex Output:
horses drcnk and graze the fceld and water

Ex Input:
Sentence: 'a small teddy bear is sitting by the pillow on the bed'. Replace the letter 'a' with 'l' in the sentence.

Ex Output:
l smlll teddy belr is sitting by the pillow on the bed