4475: 抓住那头奶牛 ( catch ) usaco 2007 Open silver

Farmer John has been informed of the location of a fugitive cow and wants to catch her immediately.
农夫约翰已经获悉逃跑的牛的位置，想立刻抓住它。

He starts at a point N (0 ≤ N ≤ 100,000) on a number line and the cow is at a point K (0 ≤ K ≤ 100,000) on the same number line. Farmer John has two modes of transportation: walking and teleporting.
农夫的位置在直线上的N (0 ≤ N ≤ 100,000)点，牛在同一直线上的 K (0 ≤ K ≤ 100,000)点，约翰有步行和闪移两种走法。

* Walking: FJ can move from any point X to the points X - 1 or X + 1 in a single minute
  步行：农夫约翰可以一分钟从点X走到X-1或X+1点
* Teleporting: FJ can move from any point X to the point 2 × X in a single minute.
  闪移：农夫约翰可以一分钟从点X走到2*X点

If the cow, unaware of its pursuit, does not move at all, how long does it take for Farmer John to retrieve it?
假设奶牛并没有意识被追，还在站在原地，农夫约翰需要多少步，才能把奶牛逮住？ 

Input

Line 1: Two space-separated integers: N and K

Output

Line 1: The least amount of time, in minutes, it takes for Farmer John to catch the fugitive cow.

Hint

The fastest way for Farmer John to reach the fugitive cow is to move along the following path: 5-10-9-18-17, which takes 4 minutes.

提示：

注意下标防止出界，注意可以回走

5 17

4