You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
In this task, you need to replace a letter in the sentence with another given letter.

Sentence: 'group of motorcycle motorists trying to merge into traffic'. Replace the letter 'o' with 'n' in the sentence.
Solution: grnup nf mntnrcycle mntnrists trying tn merge intn traffic
Why? The letter 'o' has been replaced in the letter 'n'.

New input: Sentence: 'a flat screen tv sitting in a living room'. Replace the letter 'a' with 'y' in the sentence.
Solution:
y flyt screen tv sitting in y living room