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

Example Input: Sentence: 'the man is skiing fast in the snow'. Replace the letter 'o' with 'x' in the sentence.
Example Output: the man is skiing fast in the snxw

Example Input: Sentence: 'this is a tennis player getting ready to serve the ball'. Replace the letter 'h' with 'y' in the sentence.
Example Output: tyis is a tennis player getting ready to serve tye ball

Example Input: Sentence: 'three men play a video game with wii remotes'. Replace the letter 'y' with 'f' in the sentence.
Example Output:
three men plaf a video game with wii remotes