Little Snowman

On a frosty winter day, Kasia and Asia went to the park. As winters go, the park was full of snow: to be exact, there were $x$ liters of snow in it. While Asia was on the phone, Kasia decided to build a snowman, and before Asia finished her call she had already packed one snowball out of $k$ liters of snow.

Asia wants the snowman to be made of 3 snowballs, and every snowball placed on top of another must be exactly 2 times smaller than the one directly below it. In other words, an upper ball's volume is half the volume of the ball beneath it. Kasia's snowball cannot be made bigger or smaller and must be used as it is, or Kasia might get upset.

The two girls want to build the largest snowman they can. However, they may not use more than the $x$ liters of snow available in the park. What is the maximum volume, in milliliters, of the snowman they can build? (One liter of snow equals 1000 milliliters.)

The first line contains two integers $x$ and $k$ ($1 \le x \le 10^6$, $1 \le k \le 10^5$, $k < x$). Here $x$ is the amount of snow in the park (in liters) and $k$ is the amount of snow used in the single snowball Kasia made (in liters).

Print a single integer: the maximum volume of the snowman, in milliliters. If there is not enough snow to build a snowman that satisfies the conditions, print $0$.