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

Example Input: Sentence: 'two giraffe standing in an enclosure at the zoo next to a  tree'. Replace the letter 'n' with 'g' in the sentence.
Example Output: two giraffe stagdigg ig ag egclosure at the zoo gext to a  tree

Example Input: Sentence: 'a small bird perched on a open window'. Replace the letter 'e' with 'r' in the sentence.
Example Output: a small bird prrchrd on a oprn window

Example Input: Sentence: 'a group of people at a park as a man fixes his kite'. Replace the letter 'p' with 'l' in the sentence.
Example Output:
a groul of leolle at a lark as a man fixes his kite