URI Online Judge | 1379
# Mean Median Problem

**Timelimit: 1**

By Pablo Heiber Argentina

The mean of three integers A, B and C is (A + B + C)/3. The median of three integers is the one that would be in the middle if they are sorted in non-decreasing order. Given two integers A and B, return the minimum possible integer C such that the mean and the median of A, B and C are equal.

Each test case is given in a single line that contains two integers **A** and **B** (1 ≤ **A** ≤ **B** ≤ 10^{9}). The last test case is followed by a line containing two zeros.

For each test case output one line containing the minimum possible integer **C** such that the mean and the median of **A**, **B** and **C** are equal.

Sample Input | Sample Output |

1 2 |
0 |