#include<bits/stdc++.h>
using namespace std;
#define FOR(i, a, b) for(int i = a; i < b; ++i)
#define REP(i, n) FOR(i, 0, n)
#define _ << " " <<
#define sz(x) ((int) x.size())
#define pb(x) push_back(x)
#define TRACE(x) cerr << #x << " = " << x << endl
typedef long long ll;
typedef pair<int, int> point;
const int MAXN = 17, MAX = 1 << 17, ABC = 27, inf = 1e9;
int n;
int dp[MAX], let[MAXN][ABC];
bool bio[MAX];
vector <int> visited, tmp;
int get(int mask){
int tmp[26];
REP(i, 26)
tmp[i] = inf;
REP(i, n){
if( (mask & (1 << i)) == 0) continue;
REP(j, 26)
tmp[j] = min(tmp[j], let[i][j]);
}
int ret = 0;
REP(i, 26)
ret += tmp[i];
return ret;
}
int rek(int mask){
if(dp[mask]) return dp[mask];
if(__builtin_popcount(mask) == 1) return dp[mask] = get(mask);
tmp.clear();
visited.clear();
int sub = get(mask), gen = 0;
REP(i, n){
if((1 << i) & mask){
tmp.pb(i);
gen |= (1 << i);
}
}
int ret = inf;
for (int newMask = mask - 1; newMask > 0; newMask = (newMask - 1) & newMask)
ret = min(ret, rek(newMask) + rek(newMask ^ mask) - sub);
return dp[mask] = ret;
}
int main(){
ios_base::sync_with_stdio(false); cin.tie(0);
cin >> n;
REP(i, n){
string s; cin >> s;
REP(j, sz(s))
let[i][s[j] - 'a'] ++;
}
cout << rek((1 << n) - 1) + 1;
}
