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

Example Input: Sentence: 'a table full of various types of cellphones, pdas and pagers'. Replace the letter 's' with 'f' in the sentence.
Example Output: a table full of variouf typef of cellphonef, pdaf and pagerf

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 dog wearing a hat on top of it's head'. Replace the letter 'g' with 'o' in the sentence.
Example Output:
a doo wearino a hat on top of it's head