I am posting it second time. previous code is not working. Please write the appropriate code in C programming.

Problem Statement:

If N is added to twice a number, the sum will be S. What is the number?

Input Format

The input contains two integer numbers N and S.

Note: N and S contain even number only.

Constraints

0 < N <= 200

0 < S <=500

Output Format

Output will show the one integer numbers in a separate line.

Sample Input 0

8 20 

Sample Output 0

6 

Explanation 0

if N = 8 and S = 20 then Twin Number--> 6. 8+6+6 = 20 

Sample Input 1

200 500 

Sample Output 1

150