CF1107D.Compression

You are given a binary matrix $A$ of size $n \times n$ . Let's denote an $x$ -compression of the given matrix as a matrix $B$ of size $\frac{n}{x} \times \frac{n}{x}$ such that for every $i \in [1, n], j \in [1, n]$ the condition $A[i][j] = B[\lceil \frac{i}{x} \rceil][\lceil \frac{j}{x} \rceil]$ is met.

Obviously, $x$ -compression is possible only if $x$ divides $n$ , but this condition is not enough. For example, the following matrix of size $2 \times 2$ does not have any $2$ -compression:

$01$ $10$ For the given matrix $A$ , find maximum $x$ such that an $x$ -compression of this matrix is possible.

Note that the input is given in compressed form. But even though it is compressed, you'd better use fast input.

The first line contains one number $n$ ( $4 \le n \le 5200$ ) — the number of rows and columns in the matrix $A$ . It is guaranteed that $n$ is divisible by $4$ .

Then the representation of matrix follows. Each of $n$ next lines contains $\frac{n}{4}$ one-digit hexadecimal numbers (that is, these numbers can be represented either as digits from $0$ to $9$ or as uppercase Latin letters from $A$ to $F$ ). Binary representation of each of these numbers denotes next $4$ elements of the matrix in the corresponding row. For example, if the number $B$ is given, then the corresponding elements are 1011, and if the number is $5$ , then the corresponding elements are 0101.

Elements are not separated by whitespaces.

Print one number: maximum $x$ such that an $x$ -compression of the given matrix is possible.

The first example corresponds to the matrix:

$11100111$ $11100111$ $11100111$ $00000000$ $00000000$ $11100111$ $11100111$ $11100111$ It is easy to see that the answer on this example is $1$ .