题目描述

For a string $a$ like $abcd$ the plus operation is very obvious that $a+a=abcdabcd$ but little m defined a new way to operate the strings, which is the operation minus.

For two given strings $a$ and $b$:

If the length of $a$ is not shorter than the length of $b$ then do $a-b$ else do $b-a$

$a-b$ means removing the longest sequence from $a$ by referencing $b$, and after that if there are left characters in $b$ do $a+b$ or $b+a$ if we do $b-a$ at first.

For example:

Let us define $A=aabad$ and $B=abc$

Then $A-B$ is first removing the longest sequence from $A$ by referencing $B$, after that $A=aad$ (removes $a$ at index 1 and removes $b$ at index 3, because if we can remove some characters, we will immediately remove them) after that $B=c$

Then do $A+B$, so $A-B=aadc$

For more precisely, reference only from the begin of string to the end of string and will only do once, For example:

We suppose $A=abc$ and $B=acb$ the referencing operation is first check $A[1]$, it is obvious that $A[1]=B[1]=a$ so remove both character $a$ from $A$ and $B$. Then check $A[2]$, we can see taht $A[2]!=B[2]$, so we continue referencing, then we can see that $A[3]=B[2]=c$ so we both remove character $c$ from $A$ and $B$, then we can get the answer for $A-B$ is $bb$

picture: some strings

输入格式

The first line contains one positive integer $T (1\\le T\\le 1000)$ indicating the number of the test cases.

Then for next $T$ lines, each line contains two strings $a,b (1\\le|a|,|b|\\le100)$

It is guaranteed that $a,b$ only contains lower-case English letters.

输出格式

For each test case, print one line $a-b$

样例

6 
aabad abc 
a baaa 
a aaa 
b a 
cdaab caab 
abc acb 

aadc 
baa 
aa 
ba 
d 
bb

提示

Please notice for the sixth test case $abc$-$acb$ equals $bb$