Problem:
Score : 500 points

Problem Statement

Snuke has two boards, each divided into a grid with N rows and N columns.
For both of these boards, the square at the i-th row from the top and the j-th column from the left is called Square (i,j).

There is a lowercase English letter written in each square on the first board. The letter written in Square (i,j) is S_{i,j}. On the second board, nothing is written yet.

Snuke will write letters on the second board, as follows:

First, choose two integers A and B ( 0 \leq A, B < N ).

Write one letter in each square on the second board.
Specifically, write the letter written in Square ( i+A, j+B ) on the first board into Square (i,j) on the second board.
Here, the k-th row is also represented as the (N+k)-th row, and the k-th column is also represented as the (N+k)-th column.

After this operation, the second board is called a good board when, for every i and j ( 1 \leq i, j \leq N ), the letter in Square (i,j) and the letter in Square (j,i) are equal.

Find the number of the ways to choose integers A and B ( 0 \leq A, B < N ) such that the second board is a good board.

Constraints

1 \leq N \leq 300

S_{i,j} ( 1 \leq i, j \leq N ) is a lowercase English letter.

Input

Input is given from Standard Input in the following format:

N
S_{1,1}S_{1,2}..S_{1,N}
S_{2,1}S_{2,2}..S_{2,N}
:
S_{N,1}S_{N,2}..S_{N,N}

Output

Print the number of the ways to choose integers A and B ( 0 \leq A, B < N ) such that the second board is a good board.

Sample Input 1

2
ab
ca

Sample Output 1

2

For each pair of A and B, the second board will look as shown below:

The second board is a good board when (A,B) = (0,1) or (A,B) = (1,0), thus the answer is 2.

Sample Input 2

4
aaaa
aaaa
aaaa
aaaa

Sample Output 2

16

Every possible choice of A and B makes the second board good.

Sample Input 3

5
abcde
fghij
klmno
pqrst
uvwxy

Sample Output 3

0

No possible choice of A and B makes the second board good.

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<cstdio>  
#include<algorithm>  
#include<vector>  
#include<queue>  
#include<string>  
#include<cstring>  
#include<iostream>  
#include<map>
using namespace std;
#define ll long long  
const int maxn = 1e5 + 500;
char mp[500][1000];
char a[500][500];
int n;
bool ok() {
	for (int i = 0; i < n; i++)
		for (int j = 0; j < n; j++)
			if (a[i][j] != a[j][i])
				return false;
	return true;
}
int main() {
	while (~scanf("%d", &n)) {
		int ans = 0;
		for (int i = 0; i < n; i++)
			scanf("%s", &mp[i]);
		for (int i = 0; i < n; i++)
			for (int j = 0; j < n - 1; j++)
				mp[i][j + n] = mp[i][j];
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < n; j++)
				for (int k = 0; k < n; k++)
					a[j][k] = mp[j][k + i];
			if (ok())ans += n;
		}
		cout << ans << endl;
	}
	return 0;
}