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

Example Input: Sentence: 'a person is looking out of a large window'. Replace the letter 'o' with 'p' in the sentence.
Example Output: a perspn is lppking put pf a large windpw

Example Input: Sentence: 'a man walking his dog near a sandy area'. Replace the letter 'i' with 'g' in the sentence.
Example Output: a man walkgng hgs dog near a sandy area

Example Input: Sentence: 'a dog in the air with a firsbee in its mouth and a man standing next to the dog'. Replace the letter 'a' with 'p' in the sentence.
Example Output:
p dog in the pir with p firsbee in its mouth pnd p mpn stpnding next to the dog