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

Ex Input:
Sentence: 'a baseball player is throwing a ball across the dirt field'. Replace the letter 'a' with 't' in the sentence.

Ex Output:
t btsebtll pltyer is throwing t btll tcross the dirt field


Ex Input:
Sentence: 'a woman on a cell phone on  city street'. Replace the letter 'e' with 'a' in the sentence.

Ex Output:
a woman on a call phona on  city straat


Ex Input:
Sentence: 'a large brown bear looking around near a stream'. Replace the letter 'b' with 'g' in the sentence.

Ex Output:

a large grown gear looking around near a stream