Solve the programming task below in a Python markdown code block.
*CodeChef recently revamped its [practice page] to make it easier for users to identify the next problems they should solve by introducing some new features:* 
*Recent Contest Problems - contains only problems from the last 2 contests*
*Separate Un-Attempted,  Attempted, and All tabs*
*Problem Difficulty Rating - the Recommended dropdown menu has various difficulty ranges so that you can attempt the problems most suited to your experience*
*Popular Topics and Tags*

Our Chef is currently practicing on CodeChef and is a beginner. The count of ‘All Problems’ in the Beginner section is X. Our Chef has already ‘Attempted’ Y problems among them. How many problems are yet ‘Un-attempted’?

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

- The first and only line of input contains two space-separated integers X and Y — the count of 'All problems' in the Beginner's section and the count of Chef's 'Attempted' problems, respectively. 

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

Output a single integer in a single line — the number of problems that are yet 'Un-attempted'

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

$1 ≤ Y ≤ X ≤ 1000$

------ subtasks ------ 

Subtask 1 (100 points):
Original constraints.

----- Sample Input 1 ------ 
10 4
----- Sample Output 1 ------ 
6
----- explanation 1 ------ 

----- Sample Input 2 ------ 
10 10
----- Sample Output 2 ------ 
0
----- explanation 2 ------ 

----- Sample Input 3 ------ 
1000 990
----- Sample Output 3 ------ 
10
----- explanation 3 ------ 

----- Sample Input 4 ------ 
500 1
----- Sample Output 4 ------ 
499
----- explanation 4 ------ 
Test case $1$: There are $10$ problems in total in the Beginner's section, out of which $4$ have been attempted. Hence, there are $6$ Un-attempted problems.

Test case $2$: There are $10$ problems in total in the Beginner's section, out of which all have been attempted. Hence, there are $0$ Un-attempted problems.

Test case $3$: There are $1000$ problems in total in the Beginner's section, out of which $990$ have been attempted. Hence, there are $10$ Un-attempted problems.

Test case $4$: There are $500$ problems in total in the Beginner's section, out of which only $1$ has been attempted. Hence, there are $499$ Un-attempted problems.