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

Input: Consider Input: Sentence: 'a crowd looking at a trio of planes that are sitting idle'. Replace the letter 'a' with 'e' in the sentence.

Output: e crowd looking et e trio of plenes thet ere sitting idle

Input: Consider Input: Sentence: 'a small bird perched on a open window'. Replace the letter 'e' with 'r' in the sentence.

Output: a small bird prrchrd on a oprn window

Input: Consider Input: Sentence: 'a bike parked on top of a green grass covered field'. Replace the letter 'l' with 'i' in the sentence.
Output: a bike parked on top of a green grass covered fieid