PROGRAMMING:Sort all the characters in the string from small to large

Input a string, sort the characters from small to large, and then output.
###Input format:
Enter a string no longer than 20.
###Output format:
Sort the characters from small to large and output them.
###Input example:
```in
Here is a set of inputs. For example:
defgacb
```
###Output example:
```out
The corresponding output is given here. For example:
abcdefg
```






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