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

Ex Input:
Sentence: 'a man who is surfing in a wave in the ocean'. Replace the letter 'a' with 'u' in the sentence.

Ex Output:
u mun who is surfing in u wuve in the oceun

Ex Input:
Sentence: 'a large clock on the top of pole in the middle of a walk way'. Replace the letter 'f' with 'h' in the sentence.

Ex Output:
a large clock on the top oh pole in the middle oh a walk way

Ex Input:
Sentence: 'a couple of yellow buses parked on top of a road'. Replace the letter 'p' with 'u' in the sentence.

Ex Output:
a couule of yellow buses uarked on tou of a road