#define F(i,n)for(i=n;i--;)
int n,m,d[200][202][100],a,e,z,k,l,i,j,x,y;
int main(){
	scanf("%d%d",&n,&m);a=z=2*n;
	F(k,m)F(i,n)F(j,n)scanf("%d",&e),d[k][i][j]=d[k][n+j][i]=d[k][i-j?0:z][j]=d[k][n-i-j-1?0:z+1][j]=e;
	F(k,m)F(l,k)F(i,z+2)F(j,z+2)F(x,(e=z,n))F(y,n)a=(e-=d[k][i][x]==d[l][j][y])<a?e:a;
	a=!printf("%d",a-1);
}