#include <bits/stdc++.h>
using namespace std;

int main() {
    int N, M;
    cin >> N >> M;
    int B[M][N][N];
    int L[M][N*2+2][N];
    int cnt = 0;
    for (int m = 0; m < M; ++m) {
        for (int y = 0; y < N; ++y) {
            for (int x = 0; x < N; ++x) {
                cin >> B[m][x][y];
            }
        }
    }
    for (int m = 0; m < M; ++m) {
        int c = 0;
        for (int x = 0; x < N; ++x, ++c) {
            for (int i = 0; i < N; ++i) {
                L[m][c][i] = B[m][x][i];
            }
        }
        for (int y = 0; y < N; ++y, ++c) {
            for (int i = 0; i < N; ++i) {
                L[m][c][i] = B[m][i][y];
            }
        }
        for (int i = 0; i < N; ++i) {
            L[m][c][i] = B[m][i][i];
            L[m][c+1][i] = B[m][i][N-i-1];
        }
    }
    unordered_set<int> s{};
    for (int m = 0; m < M; ++m) {
        for (int a = 0; a < N*2+2; ++a) {
            for (int i = 0; i < M; ++i) {
                if (i == m) { continue; }
                for (int j = 0, c = 0; j < N*2+2; ++j, c = 0) {
                    s.clear();
                    for (int k = 0; k < N; ++k) {
                        s.emplace(L[m][a][k]);
                        s.emplace(L[i][j][k]);
                    }
                    cnt = max(cnt, N*2-(int)s.size());
                }
            }
        }
    }
    
    cout << N+N-cnt-1 << endl;
    return 0;
}