#include "bits/stdc++.h"
using namespace std;
const int maxn = 1e6 + 6;
const int inf = 1e9;
const int MASK = (1 << 16) + 5;
int n;
int cnt[20][26];
int f[MASK];
bool check() {
for(int i = 1; i <= n; ++i) {
for(int j = 0; j < 26; ++j) {
if(cnt[i][j]) return 0;
}
}
return 1;
}
void solve() {
cin >> n;
for(int i = 1; i <= n; ++i) {
string s; cin >> s;
for(auto &j:s) {
cnt[i][j - 'a']++;
}
}
for(int mask = 0; mask < (1 << n); ++mask) {
int sum = 0;
vector<int> v(26, inf);
for(int i = 1; i <= n; ++i) {
if(mask >> (i - 1) & 1) {
for(int j = 0; j < 26; ++j) {
v[j] = min(v[j], cnt[i][j]);
}
}
}
for(int i = 0; i < 26; ++i) {
sum += v[i];
}
f[mask] = inf;
if(__builtin_popcount(mask) == 1) {
f[mask] = sum;
}
for(int sub_mask = (mask - 1) & mask; sub_mask > 0; sub_mask = (sub_mask - 1) & mask) {
f[mask] = min(f[mask], f[sub_mask] + f[mask ^ sub_mask] - sum);
}
}
cout << f[(1 << n) - 1] + 1;
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}
