#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
    int N, M;

    cin >> N >> M;

    vector<vector<vector<int> > > players(M);

    for (int i = 0; i < M; i++) {
        vector<vector<int> > card(N);
        for (int j = 0; j < N; j++) {
            vector<int> row(N);
            for (int k = 0; k < N; k++) {
                cin >> row[k];
            }
            card[j] = row;
        }
        players[i] = card;
    }

    vector<vector<vector<int> > > bingos(M);
    
    for (int i = 0; i < M; i++) {
        // left to right
        for (int j = 0; j < N; j++) {
            vector<int> lr = players[i][j];
            bingos[i].push_back(lr); 
        }

        // top to down
        for (int j = 0; j < N; j++) {
            vector<int> td(N);
            for (int k = 0; k < N; k++) {
                td[k] = players[i][k][j];
            }
            bingos[i].push_back(td);
        }
        
        // upper left to lower right
        vector<int> ullr(N);
        for (int j = 0; j < N; j++) {
            ullr[j] = players[i][j][j];
        }
        bingos[i].push_back(ullr);

        // upper right to lower left
        vector<int> urll(N);
        for (int j = 0; j < N; j++) {
            urll[j] = players[i][j][N-j-1];
        }
        bingos[i].push_back(urll);

        for (auto& bingo : bingos[i]) {
            sort(bingo.begin(), bingo.end());
        }
    }

    int answer = 2*N;
    for (int i = 0; i < M; i++) {
        for (auto& x : bingos[i]) {
            for (int j = 0; j < i; j++) {
                for (auto& y : bingos[j]) {
                    vector<int> z;
                    set_union(x.begin(), x.end(), y.begin(), y.end(), back_inserter(z));
                    answer = min(answer, (int)z.size()-1);
                }
            }
        }
    }
    cout << answer << endl;
}