# [Usaco2006 Jan] Dollar Dayz 奶牛商店

时间限制：5s 空间限制：64MB

### 题目描述

Farmer John goes to Dollar Days at The Cow Store and discovers an unlimited number of tools on sale. During his first visit, the tools are selling variously for $1, $2, and $3. Farmer John has exactly $5 to spend. He can buy 5 tools at $1 each or 1 tool at $3 and an additional 1 tool at $2. Of course, there are other combinations for a total of 5 different ways FJ can spend all his money on tools. Here they are: 1 @ US$3 + 1 @ US$2 1 @ US$3 + 2 @ US$1 1 @ US$2 + 3 @ US$1 2 @ US$2 + 1 @ US$1 5 @ US$1 Write a program than will compute the number of ways FJ can spend N dollars (1 <= N <= 1000) at The Cow Store for tools on sale with a cost of $1..$K (1 <= K <= 100).

### 输入格式

A single line with two space-separated integers: N and K.

### 输出格式

A single line with a single integer that is the number of unique ways FJ can spend his money.

### 样例输入

5 3

### 样例输出

5

### 提示

没有写明提示

### 题目来源

Silver