B. K Palindrome
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

A grid containing $$$n$$$ rows and $$$n$$$ columns is called Beautiful grid if it satisfies the following conditions :

  • Each cell conatins a lowercase English character.
  • For every $$$i(1 \le i \le n)$$$, $$$i$$$-th row is palindrome.
  • For every $$$i(1 \le i \le n)$$$, $$$i$$$-th column is palindrome.
  • The number of distinct characters in the grid is exactly $$$k$$$.

Your task is to construct any Beautiful grid for given $$$n$$$ and $$$k$$$.

Input

Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 100$$$). The description of the test cases follows.

The first line of each testcase contains two integers $$$n,k$$$ ($$$1 \le n \le 10^3$$$, $$$1 \le k \le 26$$$).

It is guaranteed that the sum of $$$n$$$ over all test cases doesn't exceed $$$10^3$$$.

Output

For each test case, print $$$-1$$$ if there is no Beautiful grid. Otherwise print $$$n$$$ strings each of length $$$n$$$.

If there are multiple answers, output any.

Example
Input
5
1 1
2 1
2 2
3 2
3 26
Output
z
kk
kk
-1
www
wyw
www
-1