#include<bits/stdc++.h>
#define F(i,n)for(int i=n;i--;)
int n,m,d[200][202][100],a,e,z;
int main(){
	std::cin>>n>>m;a=z=2*n;
	F(k,m)F(i,n)F(j,n)(std::cin>>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(i,z+2)std::sort(d[k][i],d[k][i]+n);
	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;
	std::cout<<a-1;
}