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

Example Input: Sentence: 'a man who is surfing in a wave in the ocean'. Replace the letter 'a' with 'u' in the sentence.
Example Output: u mun who is surfing in u wuve in the oceun

Example Input: Sentence: 'a toddler on skis being held up by a grownup'. Replace the letter 'o' with 'k' in the sentence.
Example Output: a tkddler kn skis being held up by a grkwnup

Example Input: Sentence: 'a cat is staring ahead as the back another cat's head is seen in front of him'. Replace the letter 'e' with 'q' in the sentence.
Example Output:
a cat is staring ahqad as thq back anothqr cat's hqad is sqqn in front of him