PROGRAMMING:toggle case
Recently, little a was so tired that he was so fascinated that he often mistook the case of letters. For example, he regarded a as a, even small a as big A. he was a little dizzy... He needed the help of smart acmers to turn the letters upside down (uppercase to lowercase, lowercase to uppercase), not output empty space, and output other characters as they are.
###Input format:
Enter a string of no more than 1000 characters. If there are spaces, consider the new string.
###Output format:
Output the corresponding converted String, each string occupies one line (Note: there is an empty line between each two answers)
###Input example:
```in
ypA cM
94ksdD
HelloWorld
```
###Output example:
```out
YPa
Cm
94KSDd
hELLOwORLD
```
answer：If there is no answer, please comment
###Input format:
Enter a string of no more than 1000 characters. If there are spaces, consider the new string.
###Output format:
Output the corresponding converted String, each string occupies one line (Note: there is an empty line between each two answers)
###Input example:
```in
ypA cM
94ksdD
HelloWorld
```
###Output example:
```out
YPa
Cm
94KSDd
hELLOwORLD
```
answer：If there is no answer, please comment