PROGRAMMING:Obsessive compulsive disorder
Xiao Ming is a patient with obsessive-compulsive disorder. One day he inadvertently let him see a string of disorderly strings. Due to compulsive psychology, he wanted to sort out the strings one by one. However, his requirements for sorting out the strings were very strict. He had to change all capital letters into lowercase letters first and sort out the strings in order. However, Xiaoming's strength does not allow QAQ, so he comes to ask for help. Can you help him?
###Input format:
First, give an integer n in the first line to represent the length of the string (1 < = n < = 400000),
The next line is given a string s, the title ensures that all characters are uppercase or lowercase letters, without any other special characters;
###Output format:
Output a line to meet Xiao Ming's "orderly" string..
###Input example:
```in
ten
asRKCpLaJp
```
###Output example:
```out
aacjklpprs
```
answer：If there is no answer, please comment
###Input format:
First, give an integer n in the first line to represent the length of the string (1 < = n < = 400000),
The next line is given a string s, the title ensures that all characters are uppercase or lowercase letters, without any other special characters;
###Output format:
Output a line to meet Xiao Ming's "orderly" string..
###Input example:
```in
ten
asRKCpLaJp
```
###Output example:
```out
aacjklpprs
```
answer：If there is no answer, please comment