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Problem 1171. -- Magic Square

## Magic Square

Time Limit: 1 Sec  Memory Limit: 64 MB
Submit: 363  Solved: 239
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## Description

In recreational mathematics, a magic square of n-degree is an arrangement of n2 numbers, distinct integers, in a square, such that the n numbers in all rows, all columns, and both diagonals sum to the same constant. For example, the picture below shows a 3-degree magic square using the integers of 1 to 9.

Given a finished number square, we need you to judge whether it is a magic square.

## Input

The input contains multiple test cases. The first line of each case stands an only integer N (0 < N < 10), indicating the degree of the number square and then N lines follows, with N positive integers in each line to describe the number square. All the numbers in the input do not exceed 1000. A case with N = 0 denotes the end of input, which should not be processed.

## Output

For each test case, print "Yes" if it's a magic square in a single line, otherwise print "No".

```2
1 2
3 4
2
4 4
4 4
3
8 1 6
3 5 7
4 9 2
4
16 9 6 3
5 4 15 10
11 14 1 8
2 7 12 13
0
```

```No
No
Yes
Yes
```

zoj2835

## Source

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