uCoder  1344  Nível: 3  Tempo Limite: 2
Mean Median Problem
Adaptado por None
Competição: Maratona de Programação da SBC 2017  Fase Nacional
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 nondecreasing order.
Write a program that, given two distinct integers A and B, determines the minimum possible integer C such that the mean and the median of A, B and C are equal.
Entrada
The input consists of a single line that contains two integers A and B (1 ≤ A ≤ B ≤ 10^{9}).
Saída
Output a single line with the minimum possible integer C such that the mean and the median of A, B and C are equal.
Exemplo de Entrada  Exemplo de Saída 

1 1000000000 
999999998

6 10 
2

1 2 
0
