#include <bits/stdc++.h>
using namespace std;
const int nx=16, kx=30;
int n, cnt[nx][kx], dp[1<<nx];
string s;
int main()
{
cin.tie(NULL)->sync_with_stdio(false);
cin>>n;
for (int i=0; i<n; i++)
{
cin>>s;
for (auto x:s) cnt[i][x-'a']++;
}
for (int msk=1; msk<(1<<n); msk++)
{
int cur=0;
for (int c=0; c<26; c++)
{
int mn=1e9;
for (int i=0; i<n; i++) if (msk&(1<<i)) mn=min(mn, cnt[i][c]);
cur+=mn;
}
if (__builtin_popcount(msk)==1)
{
dp[msk]=cur;
continue;
}
dp[msk]=1e9;
for (int sub=msk; sub>0; sub=(sub-1)&msk) dp[msk]=min(dp[msk], dp[sub]+dp[msk^sub]-cur);
}
//for (int msk=0; msk<(1<<n); msk++) cout<<"debug "<<msk<<' '<<dp[msk]<<'\n';
cout<<dp[(1<<n)-1]+1;
}
