import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Date;
import java.util.List;
import java.util.Scanner;
import java.util.Vector;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
*/public class Main {
	public static void main(String[] args) throws IOException {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		
		Reader in = new Reader();
		//Scanner in = new Scanner(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		DCompression solver = new DCompression();
		solver.solve(1, in, out);
		out.close();
	}
static class DCompression   {
	
	public static Boolean[][] pd = new Boolean[256][10]; 
	
public void solve(int testNumber, Reader in, PrintWriter out) throws IOException {

		for(int i = 0; i < 256; i++) {
			for(int j = 0; j < 10; j++) {
				pd[i][j] = null;
			}
		}
	
        int n = in.nextInt();
        char[][] matrix = new char[n][];

        in.readLine();
        for(int i = 0; i < n; i++){
            matrix[i] = in.readLine().toCharArray();
        }
        
//        n = 5200;
//        matrix = new char[n][];
//        
//        for(int i = 0; i < n; i++) {
//        	matrix[i] = new char[n/4];
//        	for(int j = 0; j < n/4; j++) matrix[i][j] = 'F';
//        }

        long time = new Date().getTime();
        List<Integer> divisores = new Vector<>();

        for(int i = 2; i <= n; i++){
            if(n % i == 0) divisores.add(i);
        }

        int piso = 0;
        int teto = divisores.size() - 1;
        int max = 1;
        int tot = 0;
        
//        for(int i = divisores.size() - 1; i >= 0; i--) {
//        	if(isOk(matrix, divisores.get(i), n, out)) {
//        		out.println(divisores.get(i));
//        		return;
//        	}
//        }
        
        while(piso <= teto) {
        	
        	int k = (teto - piso) / 2 + piso;
        	int div = divisores.get(k);
        	
        	if(isOk(matrix, div, n, out)) {
        		piso = k + 1;
        		max = Math.max(max, div);
        	}
        	else {
        		teto = teto - 1;
        	}
        	
        	tot++;
        }
        
        out.println(max);
       // out.println(tot);
       // out.println("X: " + (new Date().getTime() - time));
    }

private boolean isOk(char[][] matrix, int x, int n, PrintWriter out) {

        int m = n / x;

        for(int i = 0; i < m; i++){

            for(int j = 0; j < m; j++){

                int offsetRow = i * x;
                int offsetCol = j * x;

//                out.println("-----------------------------------------------");
//                out.println("(" + i + ", " + j + ") " + x);

                boolean ant = getValor(matrix[offsetRow][offsetCol / 4], offsetCol % 4, out);

                for(int ki = offsetRow; ki < offsetRow + x; ki++){

                    for(int kj = offsetCol; kj < offsetCol + x; kj++){

                        boolean pos = getValor(matrix[ki][kj / 4], kj % 4, out);
//                      out.print("(" + ki + ", " + kj + ") " + " -> " + pos);

                        if(pos != ant) return false;
                    }


//                    out.println();

                }

            }
        }

        return true;
    }

private boolean getValor(char v, int k, PrintWriter out) {

		if(pd[v][k] != null) return pd[v][k];
	
        int x = -1;

        if(v >= 'A') x = (v - 'A') + 10;
        else x = v - '0';
        
        int[] mask = new int[4];
        int i = 3;
        while(x > 0) {
        	mask[i] = x % 2;
        	x /= 2;
        	i--;
        }
       
        pd[v][k] = (mask[k] == 1);
        
        return pd[v][k];
    }

}
}


class Reader 
{ 
    final private int BUFFER_SIZE = 1 << 16; 
    private DataInputStream din; 
    private byte[] buffer; 
    private int bufferPointer, bytesRead; 

    public Reader() 
    { 
        din = new DataInputStream(System.in); 
        buffer = new byte[BUFFER_SIZE]; 
        bufferPointer = bytesRead = 0; 
    } 

    public Reader(String file_name) throws IOException 
    { 
        din = new DataInputStream(new FileInputStream(file_name)); 
        buffer = new byte[BUFFER_SIZE]; 
        bufferPointer = bytesRead = 0; 
    } 

    public String readLine() throws IOException 
    { 
        byte[] buf = new byte[5500]; // line length 
        int cnt = 0, c; 
        while ((c = read()) != -1) 
        { 
            if (c == '\n') 
                break; 
            buf[cnt++] = (byte) c; 
        } 
        return new String(buf, 0, cnt); 
    } 

    public int nextInt() throws IOException 
    { 
        int ret = 0; 
        byte c = read(); 
        while (c <= ' ') 
            c = read(); 
        boolean neg = (c == '-'); 
        if (neg) 
            c = read(); 
        do
        { 
            ret = ret * 10 + c - '0'; 
        }  while ((c = read()) >= '0' && c <= '9'); 

        if (neg) 
            return -ret; 
        return ret; 
    } 

    public long nextLong() throws IOException 
    { 
        long ret = 0; 
        byte c = read(); 
        while (c <= ' ') 
            c = read(); 
        boolean neg = (c == '-'); 
        if (neg) 
            c = read(); 
        do { 
            ret = ret * 10 + c - '0'; 
        } 
        while ((c = read()) >= '0' && c <= '9'); 
        if (neg) 
            return -ret; 
        return ret; 
    } 

    public double nextDouble() throws IOException 
    { 
        double ret = 0, div = 1; 
        byte c = read(); 
        while (c <= ' ') 
            c = read(); 
        boolean neg = (c == '-'); 
        if (neg) 
            c = read(); 

        do { 
            ret = ret * 10 + c - '0'; 
        } 
        while ((c = read()) >= '0' && c <= '9'); 

        if (c == '.') 
        { 
            while ((c = read()) >= '0' && c <= '9') 
            { 
                ret += (c - '0') / (div *= 10); 
            } 
        } 

        if (neg) 
            return -ret; 
        return ret; 
    } 

    private void fillBuffer() throws IOException 
    { 
        bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
        if (bytesRead == -1) 
            buffer[0] = -1; 
    } 

    private byte read() throws IOException 
    { 
        if (bufferPointer == bytesRead) 
            fillBuffer(); 
        return buffer[bufferPointer++]; 
    } 

    public void close() throws IOException 
    { 
        if (din == null) 
            return; 
        din.close(); 
    } 
}