# ZCC Loves Intersection

时间限制：1s 空间限制：128MB

### 题目描述

After beats all opponents in 3-dimension-world OI, ZCC feels bored and sets about going to other universes. In a universe with D dimension(s), ZCC finds D segments floating in the air. To be more precise: if we build a rectangular coordinate system with D axis, each of the segments is parallel with one axis, whose endpoints have a coordination of which all components belong to the set {x∈Z|0≤x＜N}. For each axis, there is exactly one segment parallel with it.

Each of the D segments changes location every second. Read the pseudo code below for more details:

Every second, from every pair of segments intersect, ZCC acquires a unit of Energy. Calculate the Expectation of the amount of the acquired energy per second please.

### 输入格式

There are several test cases in one input file. EOF indicates the end of input file.

Every test case contain two positive numbers N, D in one line.

It is guaranteed that 1＜N≤10^9, D≤99. The number of test cases≤10.

### 输出格式

For each test case, output a line with an integer or an irreducible fraction p/q, which is the Expectation.

### 样例输入

2 2 3 3 5 5

### 样例输出

1 49/81 18/625

### 提示

For the first test case of the sample input, there are 2 segments in a 2*2 lattice.

Because two endpoint couldn’t coincide, two segments must be (0,y)-(1,y) and (x,0)-(x,1). (x, y∈{0,1})

Thus, they always intersect at (x,y). As an irreducible fraction the answer is 1/1, where q = 1, so we should output an integer 1 instead.

### 题目来源

By 镇海中学