#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream> 
#include<map>
#include <iomanip>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
using namespace std;
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
#define LONG_INF 100000000000000
vector<vector<int>> neko[300];
int main() {
	int n, m;
	cin >> n >> m;
	for (int i = 0;i < m;++i) {
		vector<int> tate[110],yoko[110],w,te;
		for (int q = 0;q < n;++q) {
			for (int j = 0;j < n;++j) {
				int a;
				cin >> a;
				tate[q].push_back(a);
				yoko[j].push_back(a);
				if (q == j) w.push_back(a);
				if ((n - q - 1) == j) te.push_back(a);
			}
		}
		for (int q = 0;q < n;++q) {
			neko[i].push_back(tate[q]);
			neko[i].push_back(yoko[q]);
		}
		neko[i].push_back(w);
		neko[i].push_back(te);
	}
	int ans = 100000;
	for (int i = 0;i < m;++i) {
		for (int q = 0;q < neko[i].size();++q) {
			for (int j = i + 1;j < m;++j) {
				for (int t = 0;t < neko[j].size();++t) {
					set<int> aa;
					REP(p, neko[i][q].size()) {
						aa.insert(neko[i][q][p]);
					}
					REP(p, neko[j][t].size()) {
						aa.insert(neko[j][t][p]);
					}
					ans = min(ans, (int)aa.size());
				}
			}
		}
	}
	cout << ans-1 << endl;
	return 0;
}