/**
* @brief live archive 3401
* @file 3401.cpp
* @author mianma
* @created 2014/12/18 9:23
* @edited 2014/12/18 9:23
* @type brute
* @note
*/
#include <fstream>
#include <iostream>
#include <string>
#include <vector>
#include <cstring>
using namespace std;
#define max(a, b) ((a) > (b) ? (a) : (b))
#define min(a, b) ((a) > (b) ? (b) : (a))
#define abs(a) ((a) > 0 ? (a) : (0 - (a)))
#define CLR(vec) memset(vec, 0, sizeof(vec))
#ifdef DEBUG
ifstream in;
ofstream out;
#define CIN in
#define COUT out
#else
#define CIN cin
#define COUT cout
#endif
#define MAXV 6
#define MAXN 4
#define MAXB 24
/*if cube rot left, 0, 1, 2, 3, 4, 5 -> 1, 5, 2, 3, 0, 4*/
int lft[] = { 1, 5, 2, 3, 0, 4};
/*if cude rot up, 0, 1, 2, 3, 4, 5 -> 3, 1, 0, 5, 4, 2*/
int up[] = { 3, 1, 0, 5, 4, 2};
/*rot*/
void rot(int *dir, int *base){
int tmp[MAXV];
memcpy(tmp, base, sizeof(tmp));
for(int i = 0; i < MAXV; i++)
base[i] = tmp[dir[i]];
}
vector<string> db;
int dice[MAXB][MAXV];
int table[MAXN][MAXV];
int status[MAXN];
int n;
int ans;
/*brute all status*/
void brute(void){
int view = 0;
int tmp[MAXV];
int base[MAXV] = { 0, 1, 2, 3, 4, 5};
for(int i = 0; i < MAXV; i++){
memcpy(tmp, base, sizeof(tmp));
if(0 == i){ rot(up, tmp); }
if(1 == i){ rot(lft, tmp); rot(up, tmp); }
if(2 == i){ ;}
if(3 == i){ rot(up, tmp); rot(up, tmp); }
if(4 == i){ rot(lft, tmp); rot(lft, tmp); rot(lft, tmp); rot(up, tmp); }
if(5 == i){ rot(lft, tmp); rot(lft, tmp); rot(up, tmp); }
for(int j = 0; j < 4; j++, view++){
memcpy(dice[view], tmp, sizeof(tmp));
rot(lft, tmp);
}
}
}
void db_init(){
db.clear();
}
int db_add(string color){
int i;
for(i = 0; i < db.size(); i++)
if(db[i] == color)
return i;
db.push_back(color);
return i;
}
/*try to get better answer*/
void check_ans()
{
/*counter difference color*/
int counter[MAXB];
int tot = 0;
for(int i = 0; i < MAXV; i++){
CLR(counter);
int max_faces = 0;
for(int j = 0; j < n; j++){
int tmp = ++counter[table[j][dice[status[j]][i]]];
max_faces = max(max_faces, tmp);
}
tot += n - max_faces;
}
ans = min(tot, ans);
}
void dfs(int d){
if(d == n )
check_ans();
else{
for(int i = 0; i < MAXB; i++){
status[d] = i;
dfs(d + 1);
}
}
}
int main(void){
ios_base::sync_with_stdio(0);
#ifdef DEBUG
CIN.open("./in", ios::in);
COUT.open("./out", ios::out);
#endif
string color;
/*init status table*/
brute();
#ifdef DEBUG
for(int i = 0; i < MAXB; i++){
for(int j = 0; j < MAXV; j++)
COUT << dice[i][j] << " ";
COUT << "\n";
}
#endif
while(CIN >> n && n){
/*init color db*/
db_init();
for(int i = 0; i < n; i++)
for(int j = 0; j < MAXV; j++){
CIN >> color;
table[i][j] = db_add(color);
}
#ifdef DEBUG
/*decode color*/
for(int i = 0; i < n; i++){
for(int j = 0; j < MAXV; j++){
COUT << db[table[i][j]] << " ";
}
COUT << "\n";
}
#endif
ans = n*MAXV;
status[0] = 2;
dfs(1);
COUT << ans << "\n";
}
return 0;
}
