8-bit Zoom

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.

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 $(i,j)$.

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.

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

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

2023“钉耙编程”中国大学生算法设计超级联赛（3）