Qingshan Loves Strings
Description
Qingshan has a string $s$, while Daniel has a string $t$. Both strings only contain $\texttt{0}$ and $\texttt{1}$.
A string $a$ of length $k$ is good if and only if
- $a_i \ne a_{i+1}$ for all $i=1,2,\ldots,k-1$.
For example, $\texttt{1}$, $\texttt{101}$, $\texttt{0101}$ are good, while $\texttt{11}$, $\texttt{1001}$, $\texttt{001100}$ are not good.
Qingshan wants to make $s$ good. To do this, she can do the following operation any number of times (possibly, zero):
- insert $t$ to any position of $s$ (getting a new $s$).
Please tell Qingshan if it is possible to make $s$ good.
The input consists of multiple test cases. The first line contains a single integer $T$ ($1\le T\le 2000$) — the number of test cases. The description of the test cases follows.
The first line of each test case contains two integers $n$ and $m$ ($1 \le n,m \le 50$) — the length of the strings $s$ and $t$, respectively.
The second line of each test case contains a string $s$ of length $n$.
The third line of each test case contains a string $t$ of length $m$.
It is guaranteed that $s$ and $t$ only contain $\texttt{0}$ and $\texttt{1}$.
For each test case, print "YES" (without quotes), if it is possible to make $s$ good, and "NO" (without quotes) otherwise.
You can print letters in any case (upper or lower).
Input
The input consists of multiple test cases. The first line contains a single integer $T$ ($1\le T\le 2000$) — the number of test cases. The description of the test cases follows.
The first line of each test case contains two integers $n$ and $m$ ($1 \le n,m \le 50$) — the length of the strings $s$ and $t$, respectively.
The second line of each test case contains a string $s$ of length $n$.
The third line of each test case contains a string $t$ of length $m$.
It is guaranteed that $s$ and $t$ only contain $\texttt{0}$ and $\texttt{1}$.
Output
For each test case, print "YES" (without quotes), if it is possible to make $s$ good, and "NO" (without quotes) otherwise.
You can print letters in any case (upper or lower).
5
1 1
1
0
3 3
111
010
3 2
111
00
6 7
101100
1010101
10 2
1001001000
10
Yes
Yes
No
No
No
Note
In the first test case, $s$ is good initially, so you can get a good $s$ by doing zero operations.
In the second test case, you can do the following two operations (the inserted string $t$ is underlined):
- $\texttt{1}\underline{\texttt{010}}\texttt{11}$
- $\texttt{10101}\underline{\texttt{010}}\texttt{1}$
and get $s = \texttt{101010101}$, which is good.
In the third test case, there is no way to make $s$ good after any number of operations.