# [Nwerc2015] Elementary Math小学数学

### 题目描述

Ellen is teaching elementary math to her students and the time for the final exam has come. The exam consists of n questions. In each question the students have to add (+), subtract (−) or multiply (∗) a pair of numbers.
Ellen has already chosen the n pairs of numbers. All that remains is to decide for each pair which of the three possible operations the students should perform. To avoid students getting bored, Ellen wants to make sure that the n correct answers to her exam are all different.
Ellen给她的学生教小学数学。期末考试已经来临了。考试有n个题目，每一个题目学生们都要对一对数字进行加（+），减（-），乘（*）运算。
Ellen已经选好了n对数。剩下的是决定学生们应该对每对数执行什么运算。为了不让学生们感到厌烦，Ellen想确保n个正确答案都不一样。

### 输入格式

The input consists of:
one line with one integer n (1≤n≤2500), the number of pairs of numbers;
n lines each with two integers a and b (−10^6≤a,b≤10^6), a pair of numbers used.

### 输出格式

For each pair of numbers (a,b) in the same order as in the input, output a line containing a valid equation. Each equation should consist of five parts: a, one of the three operators, b, an equals sign (=), and the result of the expression. All the n expression results must be different.
If there are multiple valid answers you may output any of them. If there is no valid answer, output a single line with the string “impossible” instead.

### 样例输入

```Sample input 1
4
1 5
3 3
4 5
-1 -6
Sample input 2
4
-4 2
-4 2
-4 2
-4 2```

### 样例输出

```Sample output 1
1 + 5 = 6
3 * 3 = 9
4 - 5 = -1
-1 - -6 = 5

Sample output 2
impossible
```