CF520B.Two Buttons

Vasya has found a strange device. On the front panel of a device there are: a red button, a blue button and a display showing some positive integer. After clicking the red button, device multiplies the displayed number by two. After clicking the blue button, device subtracts one from the number on the display. If at some point the number stops being positive, the device breaks down. The display can show arbitrarily large numbers. Initially, the display shows number n.

Bob wants to get number m on the display. What minimum number of clicks he has to make in order to achieve this result?

瓦西娅发现了一个奇怪的设备。设备正面面板上有：一个红色按钮、一个蓝色按钮，以及一个显示某个正整数的显示屏。点击红色按钮后，设备将显示屏上的数字乘以 2；点击蓝色按钮后，设备将显示屏上的数字减去 1。如果在某时刻数字不再为正数，设备就会损坏。显示屏可以显示任意大的数字。初始时，显示屏上显示的数字为 $n$。

鲍勃希望使显示屏上最终显示数字 $m$。他至少需要点击多少次按钮才能实现这一目标？

The first and the only line of the input contains two distinct integers n and m (1 ≤ n, m ≤ 104), separated by a space .

输入仅有一行，包含两个不同的整数 $n$ 和 $m$（$1 ≤ n, m ≤ 10^4$），用空格分隔。

Print a single number — the minimum number of times one needs to push the button required to get the number m out of number n.

输出一个整数——即从数字 $n$ 得到数字 $m$ 所需按按钮的最少次数。

In the first example you need to push the blue button once, and then push the red button once.

In the second example, doubling the number is unnecessary, so we need to push the blue button nine times.

在第一个例子中，你需要按一次蓝色按钮，然后按一次红色按钮。

在第二个例子中，将数字翻倍是不必要的，因此我们需要按九次蓝色按钮。