package yukicoder;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Q452 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = Integer.parseInt(sc.next());
		int m = Integer.parseInt(sc.next());
		int[][][] table = new int[m][n][n];
		for (int i = 0; i < m; ++i) {
			for (int j = 0; j < n; ++j) {
				for (int k = 0; k < n; ++k) {
					table[i][j][k] = Integer.parseInt(sc.next());
				}
			}
		}
		ArrayList<ArrayList<Integer>>[] list = new ArrayList[m];
		for (int i = 0; i < m; ++i)
			list[i] = new ArrayList<>();

		for (int i = 0; i < m; ++i) {
			ArrayList<Integer> set3 = new ArrayList<>();
			ArrayList<Integer> set4 = new ArrayList<>();
			for (int j = 0; j < n; ++j) {
				ArrayList<Integer> set1 = new ArrayList<>();
				ArrayList<Integer> set2 = new ArrayList<>();
				for (int k = 0; k < n; ++k) {
					set1.add(table[i][j][k]);
					set2.add(table[i][k][j]);
				}
				set3.add(table[i][j][j]);
				set4.add(table[i][n - 1 - j][j]);
				list[i].add(set1);
				list[i].add(set2);
			}
			list[i].add(set3);
			list[i].add(set4);
		}

		int min = Integer.MAX_VALUE;

		for (int i = 0; i < m; ++i) {
			for (int j = i + 1; j < m; ++j) {
				for (ArrayList<Integer> set1 : list[i]) {
					for (ArrayList<Integer> set2 : list[j]) {
						Set<Integer> sum = new HashSet<>();
						sum.addAll(set1);
						sum.addAll(set2);
						min = Math.min(sum.size(), min);
					}
				}
			}
		}
		System.out.println(min - 1);
	}
}