Given a sentence and a number, substitute the word that corresponds to the given number with an antonym of the original word.
This activity is really fun. 2
This activity is really boring.
Complete the following task based on the instruction and optional input provided.### Instruction:
Given a sentence and a number, substitute the word that corresponds to the given number with an antonym of the original word.

### Input:
This activity is really fun. 2

### Output:
This activity is really boring.