#include <bits/stdc++.h>
using namespace std;
const int maxn = 19;
#define int long long
int dp[1 << maxn][maxn], n;
vector<string> s;
bool rhyme(const string& a, const string& b)
{
int u = (int)a.size() - 1, v = (int)b.size() - 1;
int cont = 0;
while(a[u] == b[v] and u >= 0 and v >= 0)
{
cont++, u--, v--;
}
if(cont >= max((int)a.size(), (int)b.size()) - 1) return true;
return false;
}
int solve(int mask, int last)
{
if(dp[mask][last] != -1) return dp[mask][last];
int ans = __builtin_popcount(mask);
for(int i = 0; i < n; i++)
{
if(mask & (1 << i)) continue;
if(rhyme(s[i], s[last]))
{
ans = max(ans, solve(mask | (1 << i), i));
}
}
//string a;
// int aux = mask;
// while(aux)
// {
// a += aux % 2 + '0';
// aux /= 2;
// }
// reverse(a.begin(), a.end());
//cout << a << "\n";
return dp[mask][last] = ans;
}
int32_t main()
{
ios::sync_with_stdio(false), cin.tie(nullptr);
cin >> n;
for(int i = 0; i < n; i++)
{
string a;
cin >> a;
s.push_back(a);
}
memset(dp, -1, sizeof(dp));
int ans = 0;
for(int i = 0; i < n; i++)
{
ans = max(ans, solve(0, i));
}
cout << ans << "\n";
}
