BSSHS-6th-FINAL

Start

2018-05-21 17:40 UTC

BSSHS-6th-FINAL

End

2018-05-24 19:15 UTC
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Problem A
R2

The number $S$ is called the mean of two numbers $R_1$ and $R_2$ if $S$ is equal to $(R_1+R_2)/2$. Mirko’s birthday present for Slavko was two integers $R_1$ and $R_2$. Slavko promptly calculated their mean which also happened to be an integer but then lost $R_2$! Help Slavko restore $R_2$.

Input

The first and only line of input contains two integers $R_1$ and $S$, both between $-1\, 000$ and $1\, 000$.

Output

Output $R_2$ on a single line.

Sample Input 1 Sample Output 1
11 15
19
Sample Input 2 Sample Output 2
4 3
2