题目描述
Problem Description
Using a specific encryption algorithm.
Given the length of a string $n$, construct a matrix such that $r \times c = n$ and $r \leq c$ with $r$ being as large as possible.
Fill the given plaintext into this $r \times c$ matrix in a top-to-bottom, left-to-right order.
The ciphertext is obtained by outputting the characters from the matrix in a left-to-right, top-to-bottom order.
Given the plaintext, output the ciphertext.
Input Format
A single line containing a string representing the plaintext.
Output Format
A single line containing a string representing the ciphertext.
Sample Input and Output
Sample Input #1
bok
Sample Output #1
bok
Sample Input #2
koaski
Sample Output #2
kakosi
Sample Input #3
boudonuimilcbsai
Sample Output #3
bombonisuuladici
Notes
Sample 3 Explanation

There are 16 characters, and for the matrix dimensions, options include $1 \times 16$, $2 \times 8$, and $4 \times 4$. Since $r$ should be as large as possible, we choose $4 \times 4$.
The matrix is filled as shown in the image.
Finally, output each character from the matrix in a left-to-right, top-to-bottom order.
Data Constraints
For 100% of the data, the input string consists only of lowercase letters and has a length not exceeding 100.
Notes
This problem is translated from COCI2007-2008 CONTEST #3 T3 TAJNA.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分