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

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

Ex Output:
a small bird prrchrd on a oprn window


Ex Input:
Sentence: 'a toilet that is being worked on with its  seat removed'. Replace the letter 't' with 'p' in the sentence.

Ex Output:
a poilep phap is being worked on wiph ips  seap removed


Ex Input:
Sentence: 'a red double decker bus on a busy street'. Replace the letter 'b' with 'x' in the sentence.

Ex Output:

a red douxle decker xus on a xusy street