#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pi;
#define mp make_pair
#define f first
#define s second
#define pb push_back
#define all(x) begin(x), end(x)
const int MOD = 1e9+7;
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template<class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
void ckmin(int& a, int b){
a = min(a, b);
}
void ckmax(int& a, int b){
a = max(a, b);
}
int N;
map<char, int> m[20];
int dp[1<<16];
int getLCP(int sub){
map<char, int> chars;
bool isFirst = 1;
for(int i = 0; i < N; i++){
if(!((sub>>i)&1)) continue;
if(isFirst){
for(auto u: m[i]){
chars[u.f] = u.s;
}
isFirst = 0;
}
else{
for(auto u: chars){
ckmin(chars[u.f], m[i][u.f]);
}
}
}
// for(auto u: chars){
// cout << u.f << " " << u.s << "\n";
// }
int sum = 1;
for(auto u: chars){
sum+=u.s;
}
return sum;
}
int main(){
cin.tie(0)->sync_with_stdio(0);
cin >> N;
for(int i = 0; i < N; i++){
string s;
cin >> s;
for(auto u: s){
m[i][u]++;
}
}
for(int i = 1; i < (1<<N); i++){
//cout << "i: " << i << "\n";
int bit_num = 0;
for(int j = 0; j < N; j++){
if((i>>j)&1){
bit_num++;
}
}
if(bit_num == 1){
dp[i] = getLCP(i);
}
else{
dp[i] = MOD;
for(int j = i;; j=((j-1)&i)){
if(i-j != 0 && j != 0){
ckmin(dp[i], dp[j]+dp[i-j]);
}
if(j == 0) break;
}
dp[i]-=getLCP(i);
}
}
cout << dp[(1<<N)-1] << "\n";
// for(int i = 1; i < (1<<N); i++){
// cout << i << " " << dp[i] << "\n";
// }
}
