#include <iostream>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>
#include <list>
#include <vector>
#include <complex>
#include <utility>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <bitset>
#include <ctime>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <cassert>
#include <cstddef>
#include <iomanip>
#include <numeric>
#include <tuple>
#include <sstream>
#include <fstream>
#include <chrono>
#include <random>

using namespace std;
#define REP(i, n) for (int (i) = 0; (i) < (n); (i)++)
#define FOR(i, a, b) for (int (i) = (a); (i) < (b); (i)++)
#define RREP(i, a) for(int (i) = (a) - 1; (i) >= 0; (i)--)
#define FORR(i, a, b) for(int (i) = (a) - 1; (i) >= (b); (i)--)
#define DEBUG(C) cerr << #C << " = " << C << endl;
using LL = long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<LL>;
using VVL = vector<VL>;
using VD = vector<double>;
using VVD = vector<VD>;
using PII = pair<int, int>;
using PDD = pair<double, double>;
using PLL = pair<LL, LL>;
using VPII = vector<PII>;
template<typename T> using VT = vector<T>;
#define ALL(a) begin((a)), end((a))
#define RALL(a) rbegin((a)), rend((a))
#define SORT(a) sort(ALL((a)))
#define RSORT(a) sort(RALL((a)))
#define REVERSE(a) reverse(ALL((a)))
#define MP make_pair
#define FORE(a, b) for (auto &&a : (b))
#define FIND(s, e) ((s).find(e) != (s).end())
#define EB emplace_back

const int INF = 1e9;
const int MOD = INF + 7;
const LL LLINF = 1e18;

int N, M;
VT<VVI> C;
VT<VVI> bingo;
VI buf1(N), buf2(N);

int main(void) {
    scanf("%d%d", &N, &M);
    C.resize(M, VVI(N, VI(N)));
    REP(i, M)REP(j, N)REP(k, N) {
        scanf("%d", &C[i][j][k]);
    }
    //bingo.resize(M, VVI(N * 2 + 2));
    bingo.resize(M, VVI(N * 2 + 2, VI(N)));
    REP(num, M) {
        REP(i, N) {
            REP(j, N) {
                bingo[num][i * 2][j] = C[num][i][j];
                bingo[num][i * 2 + 1][j] = C[num][j][i];
            }
        }
        REP(i, N) {
            bingo[num][N * 2][i] = C[num][i][i];
            bingo[num][N * 2 + 1][i] = C[num][i][N - i - 1];
        }
    }
    
    int ans = INF;
    
    REP(i, M) REP(j, M) {
        if (i == j) continue;
        FORE(bingo1, bingo[i])FORE(bingo2, bingo[j]) {
            unordered_set<int> se;
            FORE(e, bingo1) se.insert(e);
            FORE(e, bingo2) se.insert(e);
            ans = min(ans, (int)se.size() - 1);
        }
    }
    cout << ans << endl;
}