Swapping Chefs Way

 Chef is working on his swap-based sorting algorithm for strings.

Given a string S$S$ of length N$N$, he wants to know whether he can sort the string using his algorithm.

According to the algorithm, one can perform the following operation on string S$S$ any number of times:

• Choose some index i$i$ (1≤i≤N)$(1\le i\le N)$ and swap the ith$i^{th}$ character from the front and the ith$i^{th}$ character from the back.
  More formally, choose an index i$i$ and swap Si$S_i$ and S(N+1−i)$S_{(N+1-i)}$.

For example, d––cba––$\underset{\_}{\mathtt{\text{d}}}\mathtt{\text{cb}}\underset{\_}{\mathtt{\text{a}}}$ can be converted to a––cbd––$\underset{\_}{\mathtt{\text{a}}}\mathtt{\text{cb}}\underset{\_}{\mathtt{\text{d}}}$ using one operation where i=1$i=1$.

Help Chef find if it is possible to sort the string using any (possibly zero) number of operations.

Input Format

• The first line of the input contains a single integer T$T$, denoting the number of test cases. The description of T$T$ test cases follows.
• The first line of each test case contains N$N$, the length of the string.
• The second line contains a string S$S$ of length N$N$ consisting of lowercase letters of the Latin alphabet.

Output Format

For each test case, print YES$\mathtt{\text{YES}}$ if it is possible to sort the string by performing any number of operations. Otherwise, print NO$\mathtt{\text{NO}}$.

You may print each character of the string in uppercase or lowercase (for example, the strings YeS$\mathtt{\text{YeS}}$, yEs$\mathtt{\text{yEs}}$, yes$\mathtt{\text{yes}}$ and YES$\mathtt{\text{YES}}$ will all be treated as identical).

Constraints

• 1≤T≤100$1\le T\le 100$
• 1≤N≤103$1\le N\le {10}^3$
• Sum of N$N$ over all test cases does not exceed 2⋅103$2\cdot {10}^3$.
• S$S$ consists of lowercase Latin alphabets only.

Sample Input 1 

3
4
dbca
3
ccc
3
bza

Sample Output 1 

YES
YES
NO

Explanation

Test case 1$1$: Chef can sort the string using 1$1$ operation.

• Choose i=1$i=1$ and swap S1=d$S_1=\mathtt{\text{d}}$ and S4=a$S_4=\mathtt{\text{a}}$. This way, the string becomes abcd$\mathtt{\text{abcd}}$.

Hence, the string is sorted.

Test case 2$2$: Chef needs 0$0$ operations to sort this string as it is already sorted.

Test case 3$3$: It can be proven that the given string cannot be sorted using any number of operations.