TASK DEFINITION: In this task, you need to replace a letter in the sentence with another given letter.
PROBLEM: Sentence: 'a person on a surfboard riding in ocean waves'. Replace the letter 's' with 'g' in the sentence.

SOLUTION: a pergon on a gurfboard riding in ocean waveg

PROBLEM: Sentence: 'a family opens gifts in a room with their dog, while sitting on couches'. Replace the letter 's' with 'l' in the sentence.

SOLUTION: a family openl giftl in a room with their dog, while litting on couchel

PROBLEM: Sentence: 'an old propellor airplane with targets on the wings is in the sky'. Replace the letter 'r' with 'm' in the sentence.

SOLUTION:
an old pmopellom aimplane with tamgets on the wings is in the sky