import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.BufferedWriter;
import java.util.InputMismatchException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.io.InputStream;

/**
 * Built using CHelper plug-in Actual solution is at the top
 *
 * @author @Ziklon
 */
public class Main {
  public static void main(String[] args) {
    InputStream inputStream = System.in;
    OutputStream outputStream = System.out;
    InputReader in = new InputReader(inputStream);
    OutputWriter out = new OutputWriter(outputStream);
    DCompression solver = new DCompression();
    solver.solve(1, in, out);
    out.close();
  }

  static class DCompression {
    int toDec(char c) {
      if (Character.isDigit(c)) return c - '0';
      return c - 'A' + 10;
    }

    int[] toBinary(int n) {
      int[] ans = new int[4];
      for (int i = 0; i < 4; ++i) {
        ans[4 - i - 1] = n % 2;
        n /= 2;
      }
      return ans;
    }

    boolean check(boolean[][] table, int m) {
      int div = table.length / m;
      for (int i = 0; i < table.length; ++i)
        for (int j = 0; j < table.length; j++) {
          if (table[i][j] != table[i % div][j % div]) return false;
        }
      return true;
    }

    public void solve(int testNumber, InputReader in, OutputWriter out) {

      int n = in.readInt();
      boolean table[][] = new boolean[n][n];
      for (int i = 0; i < n; ++i) {
        String s = in.readString();
        for (int j = 0; j < n / 4; ++j) {
          int[] row = toBinary(toDec(s.charAt(j)));
          for (int k = 0; k < 4; ++k) {
            table[i][(j * 4) + k] = row[k] == 1 ? true : false;
          }
        }
      }
      List<Integer> divisors = new ArrayList<>();
      for (int i = 1; i <= n; ++i) {
        if (n % i == 0) divisors.add(i);
      }

      int low = 0, hih = divisors.size();
      while (hih - low > 1) {
        int middle = (low + hih) >> 1;
        if (check(table, divisors.get(middle))) low = middle;
        else hih = middle - 1;
      }
      if (low + 1 < divisors.size() && check(table, divisors.get(low + 1))) low++;
      out.printLine(divisors.get(low));
    }
  }

  static class OutputWriter {
    private final PrintWriter writer;

    public OutputWriter(OutputStream outputStream) {
      writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public OutputWriter(Writer writer) {
      this.writer = new PrintWriter(writer);
    }

    public void close() {
      writer.close();
    }

    public void printLine(int i) {
      writer.println(i);
    }
  }

  static class InputReader {
    private InputStream stream;
    private byte[] buf = new byte[1024];
    private int curChar;
    private int numChars;
    private InputReader.SpaceCharFilter filter;

    public InputReader(InputStream stream) {
      this.stream = stream;
    }

    public int read() {
      if (numChars == -1) {
        throw new InputMismatchException();
      }
      if (curChar >= numChars) {
        curChar = 0;
        try {
          numChars = stream.read(buf);
        } catch (IOException e) {
          throw new InputMismatchException();
        }
        if (numChars <= 0) {
          return -1;
        }
      }
      return buf[curChar++];
    }

    public int readInt() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      int sgn = 1;
      if (c == '-') {
        sgn = -1;
        c = read();
      }
      int res = 0;
      do {
        if (c < '0' || c > '9') {
          throw new InputMismatchException();
        }
        res *= 10;
        res += c - '0';
        c = read();
      } while (!isSpaceChar(c));
      return res * sgn;
    }

    public String readString() {
      int c = read();
      while (isSpaceChar(c)) {
        c = read();
      }
      StringBuilder res = new StringBuilder();
      do {
        if (Character.isValidCodePoint(c)) {
          res.appendCodePoint(c);
        }
        c = read();
      } while (!isSpaceChar(c));
      return res.toString();
    }

    public boolean isSpaceChar(int c) {
      if (filter != null) {
        return filter.isSpaceChar(c);
      }
      return isWhitespace(c);
    }

    public static boolean isWhitespace(int c) {
      return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public interface SpaceCharFilter {
      public boolean isSpaceChar(int ch);
    }
  }
}
