How many unattempted problems

 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$X$. Our Chef has already ‘Attempted’ Y$Y$ 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$X$ and Y$Y$ — 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$1\le Y\le X\le 1000$

Subtasks

• Subtask 1 (100 points):
  • Original constraints.

Sample Input 1 

10 4

Sample Output 1 

6

Sample Input 2 

10 10

Sample Output 2 

0

Sample Input 3 

1000 990

Sample Output 3 

10

Sample Input 4 

500 1

Sample Output 4 

499

Explanation

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

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

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

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