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

Example Input: Sentence: 'a black and white photo of a bird clouds sand and water'. Replace the letter 'b' with 'p' in the sentence.
Example Output: a plack and white photo of a pird clouds sand and water

Example Input: Sentence: 'the dog lies inside a purple and white collapsable chair'. Replace the letter 'n' with 'j' in the sentence.
Example Output: the dog lies ijside a purple ajd white collapsable chair

Example Input: Sentence: 'people are running around on a field and throwing frisbees'. Replace the letter 'u' with 'c' in the sentence.
Example Output:
people are rcnning arocnd on a field and throwing frisbees