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

Example Input: Sentence: 'a man getting ready to hit a ball at a baseball game'. Replace the letter 'n' with 'v' in the sentence.
Example Output: a mav gettivg ready to hit a ball at a baseball game

Example Input: Sentence: 'giraffes behind a fence in the trees'. Replace the letter 'h' with 'l' in the sentence.
Example Output: giraffes belind a fence in tle trees

Example Input: Sentence: 'two police men are on motorcycles with some american flags'. Replace the letter 'o' with 't' in the sentence.
Example Output:
twt ptlice men are tn mtttrcycles with stme american flags