8-bit Zoom

Problem Description

You are given a picture with size $n\times n$. You need to output the zoomed picture with the zooming rate $Z\%$ in 8-bit style, or determine the picture can not be zoomed. Here in 8-bit style, the size of the result picture is $\frac{nZ}{100}\times \frac{nZ}{100}$. A picture can not be zoomed in 8-bit style if and only if any of the following holds:

• $\frac{nZ}{100}$ is not an integer.
• In the zoomed picture, the color of some pixels can not be determined. Note that there aren't any interpolation algorithm applied in 8-bit style, so when at least two different colors are mapped into the same pixel in the resulting picture, the color of this pixel is undetermined.

Input

The first line contains a single integer $T$ ($1 \leq T \leq 10$), the number of test cases. For each test case: The first line contains two integers $n$ and $Z$ ($1\leq n\leq 50$, $100\leq Z\leq 200$, $Z\bmod25=0$), denoting the size of the original picture and the zooming rate. Each of the following $n$ lines contains a string of length $n$, consisting of lowercase English letters. The $j$-th character in the $i$-th line denotes the color of the pixel located at $(i,j)$.

Output

For each test case, if the picture can not be zoomed, print ''$\texttt{error}$'' in a line, otherwise print $\frac{nZ}{100}$ lines, each line contains a string of length $\frac{nZ}{100}$, denoting the resulting picture.

Sample Input

5
2 100
ab
cd
2 200
ab
cd
2 125
aa
aa
4 125
aaab
aaaa
aaaa
aaaa
4 125
aaaa
aaaa
aaaa
aaaa

Sample Output

ab
cd
aabb
aabb
ccdd
ccdd
error
error
aaaaa
aaaaa
aaaaa
aaaaa
aaaaa

Source

2023“钉耙编程”中国大学生算法设计超级联赛（3）