You are an expert competitive programmer. You will be given a problem statement, test case constraints and example test inputs and outputs. Please reason step by step about the solution (that must respect memory and time limits), then provide a complete implementation in c++17.

Your solution must read input from standard input (cin), write output to standard output (cout).
Do not include any debug prints or additional output.

Put your final solution within a single code block:
```cpp
<your code here>
```

Execution time limit: 2.0 seconds
Memory limit: 256.0 MB

# Problem
Ashish has two strings $$$a$$$ and $$$b$$$, each of length $$$n$$$, and an integer $$$k$$$. The strings only contain lowercase English letters.

He wants to convert string $$$a$$$ into string $$$b$$$ by performing some (possibly zero) operations on $$$a$$$.

In one move, he can either

- choose an index $$$i$$$ ($$$1 \leq i\leq n-1$$$) and swap $$$a_i$$$ and $$$a_{i+1}$$$, or
- choose an index $$$i$$$ ($$$1 \leq i \leq n-k+1$$$) and if $$$a_i, a_{i+1}, \ldots, a_{i+k-1}$$$ are all equal to some character $$$c$$$ ($$$c \neq$$$ 'z'), replace each one with the next character $$$(c+1)$$$, that is, 'a' is replaced by 'b', 'b' is replaced by 'c' and so on.

Note that he can perform any number of operations, and the operations can only be performed on string $$$a$$$.

Help Ashish determine if it is possible to convert string $$$a$$$ into $$$b$$$ after performing some (possibly zero) operations on it.

## Input Format
The first line contains a single integer $$$t$$$ ($$$1 \leq t \leq 10^5$$$) — the number of test cases. The description of each test case is as follows.

The first line of each test case contains two integers $$$n$$$ ($$$2 \leq n \leq 10^6$$$) and $$$k$$$ ($$$1 \leq k \leq n$$$).

The second line of each test case contains the string $$$a$$$ of length $$$n$$$ consisting of lowercase English letters.

The third line of each test case contains the string $$$b$$$ of length $$$n$$$ consisting of lowercase English letters.

It is guaranteed that the sum of values $$$n$$$ among all test cases does not exceed $$$10^6$$$.

## Output Format
For each test case, print "Yes" if Ashish can convert $$$a$$$ into $$$b$$$ after some moves, else print "No".

You may print the letters of the answer in any case (upper or lower).

## Examples
```input
4
3 3
abc
bcd
4 2
abba
azza
2 1
zz
aa
6 2
aaabba
ddddcc
```
```output
No
Yes
No
Yes
```

## Note
In the first test case it can be shown that it is impossible to convert $$$a$$$ into $$$b$$$.

In the second test case,

"abba" $$$\xrightarrow{\text{inc}}$$$ "acca" $$$\xrightarrow{\text{inc}}$$$ $$$\ldots$$$ $$$\xrightarrow{\text{inc}}$$$ "azza".

Here "swap" denotes an operation of the first type, and "inc" denotes an operation of the second type.

In the fourth test case,

"aaabba" $$$\xrightarrow{\text{swap}}$$$ "aaabab" $$$\xrightarrow{\text{swap}}$$$ "aaaabb" $$$\xrightarrow{\text{inc}}$$$ $$$\ldots$$$ $$$\xrightarrow{\text{inc}}$$$ "ddaabb" $$$\xrightarrow{\text{inc}}$$$ $$$\ldots$$$ $$$\xrightarrow{\text{inc}}$$$ "ddddbb" $$$\xrightarrow{\text{inc}}$$$ $$$\ldots$$$ $$$\xrightarrow{\text{inc}}$$$ "ddddcc".

Now solve the problem and return the code.