PROGRAMMING:Hello, world!

Say "Hello" to the world.
Show "Hello, world!" on the screen.
### Input Specification:
No input.
### Output Specification:
Print "*Hello, world!* " in one line. No space before and behind the sentence. 1 space behind comma(','). 1 exclamation mark('!') behind "world".
### Sample Input:
```in
```
### Sample Output:
```out
Hello, world!
```







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