#include <iostream>
#include <algorithm>
#include <set>
#include <vector>
#define rep(i, n) for (i = 0; i < n; i++)
using namespace std;

int n, m;
int c[200][100][100];

int f(int a, int b) {
	int i, j, k;
	vector<vector<int>> as; as.resize(2 * n + 2); rep(i, 2 * n + 2) as[i].resize(n);
	vector<vector<int>> bs; bs.resize(2 * n + 2); rep(i, 2 * n + 2) bs[i].resize(n);
	
	rep(i, n) rep(j, n) as[i][j] = c[a][i][j];
	rep(i, n) rep(j, n) as[n + i][j] = c[a][j][i];
	rep(i, n) as[2 * n][i] = c[a][i][i];
	rep(i, n) as[2 * n + 1][i] = c[a][i][n - 1 - i];
	
	rep(i, n) rep(j, n) bs[i][j] = c[b][i][j];
	rep(i, n) rep(j, n) bs[n + i][j] = c[b][j][i];
	rep(i, n) bs[2 * n][i] = c[b][i][i];
	rep(i, n) bs[2 * n + 1][i] = c[b][i][n - 1 - i];
	
	int ret = 114514;
	rep(i, 2 * n + 2) {
		rep(j, 2 * n + 2) {
			set<int> dict;
			rep(k, n) { dict.insert(as[i][k]); dict.insert(bs[j][k]); }
			ret = min(ret, (int)dict.size());
		}
	}
	return ret;
}

int main() {
	int i, j, k;
	
	cin >> n >> m;
	rep(i, m) rep(j, n) rep(k, n) cin >> c[i][j][k];
	
	int ans = 114514;
	for (i = 0; i < m; i++) for (j = i + 1; j < m; j++) ans = min(ans, f(i, j) - 1);
	cout << ans << endl;
	return 0;
}