OnlineJudge 3 现已推出。点此体验新版：Combinatorial mathematics | SDUT OnlineJudge

### Combinatorial mathematics

Time Limit: 1000 ms
Memory Limit: 65536 KiB

#### Problem Description

As you know, shadow95 is pretty good at maths, especially combinatorial mathematics. Now, he has made a problem for you. We call a subset which exactly has r elements as a "r-subset".For example, {1,2,5} is a 3-subset(r=3) of {1,2,3,4,5}. Now, your task is to form all the r-subset of {1,2,...,n}, then output them in lexicographic order（字典序）.

#### Input

The input file ends by EOF.

For each test case, there are two integer n,r.(1 <= r < n <= 20)

#### Output

First output the case number, then output all the r-subset of {1,2,...,n} in lexicographic order.

Each case seperates by a blank line.

#### Sample Input

3 2 3 1

#### Sample Output

Case #1: 1 2 1 3 2 3 Case #2: 1 2 3

#### Hint

#### Source

HDU shadow95