Two Buttons

一个设备可支持两种操作： 1. 将当前数 $\times 2$ 。 2. 将当前数 $-1$ 。 另外，当设备中的数不是正数时，设备将会崩溃。 现在给出两个数 $n,m$ ，问你需要多少次操作才能将 $n$ 变成 $m$ 。 输入两个正整数 $n,m$ 。 输出一个正整数代表问题的答案。

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?

The first and the only line of the input contains two distinct integers $ n $ and $ m $ ( $ 1<=n,m<=10^{4} $ ), separated by a space .

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 $ .

4 6

2

10 1

9

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.