TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a dog with his tongue out riding on a skateboard'. Replace the letter 's' with 'b' in the sentence.

SOLUTION: a dog with hib tongue out riding on a bkateboard

PROBLEM: Sentence: 'a room with a bed, lamps, tables and pillows'. Replace the letter 's' with 'b' in the sentence.

SOLUTION: a room with a bed, lampb, tableb and pillowb

PROBLEM: Sentence: 'a man smoking a cigarette and standing by a bicycle'. Replace the letter 'b' with 's' in the sentence.

SOLUTION:
a man smoking a cigarette and standing sy a sicycle