2211. The number of n-k-special sets

单点时限: 2.0 sec

内存限制: 256 MB

We say that a set X of natural numbers is n-k-special if:

  1. for every x belonging to the set X: 1 <= x <= n,

  2. the sum of all integers from X is greater than k,

  3. X does not contain a pair of consecutive natural numbers.

Write a program that:

  • reads two natural numbers n and k,

  • computes the number of n-k-special sets,

  • writes the result.

输入格式

In the first line there are two natural numbers n and k separated by a single space, 1 <= n <= 100, 0 <= k <= 400.

输出格式

In the first line there should be written one non-negative integer, which equals the number of n-k-special sets for the given n and k.

样例

Input
5 6
Output
3

4 人解决,6 人已尝试。

5 份提交通过,共有 14 份提交。

7.7 EMB 奖励。

创建: 11 年,6 月前.

修改: 2 年,5 月前.

最后提交: 11 月,1 周前.

来源: POI 1997 III Stage

题目标签
DP