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

Ex Input:
Sentence: 'a close shot of a stop sign near a building'. Replace the letter 'b' with 'u' in the sentence.

Ex Output:
a close shot of a stop sign near a uuilding


Ex Input:
Sentence: 'a gray elephant standing next to green bushes'. Replace the letter 'e' with 'o' in the sentence.

Ex Output:
a gray olophant standing noxt to groon bushos


Ex Input:
Sentence: 'there is a small bowl with a lot of food in it'. Replace the letter 't' with 'y' in the sentence.

Ex Output:

yhere is a small bowl wiyh a loy of food in iy