问题 3012. -- 抓住那头奶牛 ( catch ) usaco 2007 Open silver

3012: 抓住那头奶牛 ( catch ) usaco 2007 Open silver

时间限制: 1 Sec  内存限制: 128 MB
献花: 1  解决: 0
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题目描述



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 - 1 or + 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.

Sample Input

5 17

Sample Output

4

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

输入

输出

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来源

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