Solve the programming task below in a Python markdown code block.
For the upcoming semester, the admins of your university decided to keep a total of X seats for the MATH-1 course. A student interest survey was conducted by the admins and it was found that Y students were interested in taking up the MATH-1 course.

Find the minimum number of extra seats that the admins need to add into the MATH-1 course to make sure that every student who is interested in taking the course would be able to do so.

------ Input Format ------ 

- The first line of input will contain a single integer T, denoting the number of test cases.
- Each test case consists of two-space separated integers on a single line, X and Y — the current number of seats up for enrolment and the number of students interested in taking up the course in the upcoming semester, respectively.

------ Output Format ------ 

For each test case, output on a new line the minimum number of seats required to be added.

------ Constraints ------ 

$1 ≤ T ≤ 100$
$1 ≤ X, Y ≤ 10^{5}$

----- Sample Input 1 ------ 
4
1 1
12 34
50 49
49 50

----- Sample Output 1 ------ 
0
22
0
1
----- explanation 1 ------ 
Test case $1$: Exactly $1$ seat is available for enrolment, and exactly $1$ student is interested in taking up the course, hence addition of more seats is not required.

Test case $2$: $12$ seats are available for enrolment but $34$ students are interested in taking up the course, hence the admins would have to add $34-12=22$ more seats to make sure that every student interested in the course gets a seat.

Test case $3$: $50$ seats are available for enrolment and $49$ students are interested in taking up the course, hence addition of more seats is not required.

Test case $4$: $49$ seats are available for enrolment, but $50$ students are interested in taking up the course, hence the admins would have to add $50-49=1$ more seat to make sure that every student interested in the course gets a seat.