#include<bits/stdc++.h>

using namespace std;
typedef unsigned int uint;
typedef long long int ll;
typedef unsigned long long int ull;

#define debugv(v) printf("L%d %s => ",__LINE__,#v);for(auto e:v){cout<<e<<" ";}cout<<endl;
#define debugm(m) printf("L%d %s is..\n",__LINE__,#m);for(auto v:m){for(auto e:v){cout<<e<<" ";}cout<<endl;}
#define debuga(m,w) printf("L%d %s is => ",__LINE__,#m);for(int x=0;x<(w);x++){cout<<(m)[x]<<" ";}cout<<endl;
#define debugaa(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[x][y]<<" ";}cout<<endl;}
#define ALL(v) (v).begin(),(v).end()
#define BIGINT 0x7FFFFFFF
#define E107 1000000007
void printbit(int u){if(u==0)cout<<0;else{int s=0,k=0;for(;0<u;u>>=1,k++)s=(s<<1)|(u&1);for(;0<k--;s>>=1)cout<<(s&1);}}

#define TIME chrono::system_clock::now()
#define MILLISEC(t) (chrono::duration_cast<chrono::milliseconds>(t).count())

template<typename T1,typename T2>
ostream& operator <<(ostream &o,const pair<T1,T2> p){o<<"("<<p.first<<":"<<p.second<<")";return o;}

int width,height;
int m,n;

vector<vector<int>> bingo[200];

int cpa[105],cpb[105];

int main(){
    int i,j,k;
    int x,y,a,b;
    
    cin >> n >> m;
    
    for (i=0;i<m;i++){
        bingo[i].resize(n);
        for (y=0;y<n;y++){
            bingo[i][y].resize(n);
            for (x=0;x<n;x++){
                scanf("%d",&bingo[i][y][x]);
            }
        }
    }
    
    int result = n*2;
    
    set<int> sa,ss;
    for (i=0;i<m-1;i++){
        for (a=0;a<n*2+2;a++){
            sa.clear();
            if (a<n){
                for (k=0;k<n;k++){
                    sa.insert(bingo[i][a][k]);
                }
            }else if (a<2*n){
                for (k=0;k<n;k++){
                    sa.insert(bingo[i][k][a-n]);
                }
            }else if (a==2*n){
                for (k=0;k<n;k++){
                    sa.insert(bingo[i][k][k]);
                }
            }else{
                for (k=0;k<n;k++){
                    sa.insert(bingo[i][k][n-k-1]);
                }
            }
            for (j=i+1;j<m;j++){
                for (b=0;b<n*2+2;b++){
                    ss=sa;
                    if (b<n){
                        for (k=0;k<n;k++){
                            ss.insert(bingo[j][b][k]);
                        }
                    }else if (b<2*n){
                        for (k=0;k<n;k++){
                            ss.insert(bingo[j][k][b-n]);
                        }
                    }else if (b==2*n){
                        for (k=0;k<n;k++){
                            ss.insert(bingo[j][k][k]);
                        }
                    }else{
                        for (k=0;k<n;k++){
                            ss.insert(bingo[j][k][n-k-1]);
                        }
                    }
                    result = min(result,(int)ss.size());
                }
            }
        }
    }
    
    cout << result-1 << endl;
    
    return 0;
}