Given a string S which contains only small letters. The task is to make a square matrix from string S. Then perform the following operations.
1. In each column delete the characters which occur more than one.
2. Column-wise sort the remaining characters in order abcd....wxyz. But print them in order azbycxdw....
For example, after operation 1 if the remaining characters in a column are cedjki then after sorting they become cdeijk , now when printed in the given order the output will be ckdjei. If there's no character remaining Print 0.
Note: Length of the Input String is always a Perfect Square.

Example 1:
Input:
S = "adgkbdhlceilcfjm"
Output:
abefgjhikm
Explanation:
Matrix will be
a d g k
b d h l
c e i l
c f j m
In 1st column 'c', in 2nd column 'd' and in
4th column 'l' has occurred more than once.
So after deleting them and sorting the
remaining characters the matrix become
a - g k
b - h -
- e i -
- f j m
So after operation 2 we get 'ab' from 1st
column, 'ef' from 2nd column, 'gjhi' from
3rd column and 'km' from 4th column. Appending
all of them we get the output as "abefgjhikm".
Example 2:
Input:
S = "abcabcabc"
Output:
0
Explanation:
Matrix will be
a b c
a b c
a b c
So, There will be no letters remaining
and the output will be 0.

Your Task:
You don't need to read input or print anything. Your task is to complete the function matrixGame() which takes a String S and returns the answer.

Expected Time Complexity: O(|S|)
Expected Auxiliary Space: O(1)

Constraints
1 <= |S| <= 10^{5}

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